Walking on streets-in-the-sky: structures for democratic cities

ABSTRACT Streets-in-the-sky were conceptualized by architects Alison and Peter Smithson as collective space, an articulation between individual and civitas. This essay argues that streets-in-the-sky are a particularly democratic type of urban element, which also has many positive sustainability potentials. The first use of this concept was in the Smithson’s unbuilt Golden Lane estate (1952), which became a hallmark in post-WW2 debates over urban structure, domesticity, and social housing. Park Hill, the first streets-in-the-sky estate by Jack Lynn and Ivor Smith, was a success in the 1960s. The Smithsons continued to explore the idea in several urban projects, only to put it to built form in Robin Hood Gardens (1968–1972). These estates have adapted streets-in-the-sky and afterward evolved to very different states of maturity. While Park Hill is a refurbished Grade II listed building, Robin Hood Gardens is awaiting full demolition. Streets-in-the-sky were generally abandoned in more recent housing schemes, but the situation of these estates suggests that no consensus exists as to their urban value. Here, we analyze streets-in-the-sky at the time of their emergence as a concept. To assess their cultural, morphological, social, and political implications, we explore their development in built and unbuilt housing schemes, using the abovementioned case-studies to point out how streets-in-the-sky evolved, including their possible role in important urban debates of the present. Since many social housing estates employing streets-in-the-sky have been and continue to be demolished in redevelopment projects, we aim to understand what losses—aesthetic, functional, and environmental—may be implied in the decimation of this element of urban form.


Introduction
Architects Alison and Peter Smithson (1928Smithson ( -1993Smithson ( and 1923Smithson ( -2003 started working in the London County Council School Department in 1949 (Johnson and Langmead 1997, 312). In that same year, they designed the Hunstanton School  in Norwich. In 1952, a competition for the Golden Lane estate (London) led them to partake in postwar debates on housing shortage and mobility. The latter is also fundamental in their 1953 Sheffield University competition entry. In 1953, "Architectural Design" (AD) published the project for a small (unbuilt) house for the architects themselves, calling for a "warehouse aesthetics", a sincere enjoyment of industrial and modern materials (Smithson and Smithson 1953). As they got involved in the MARS Group, in 1953 they presented an urban plan derived from Golden Lane in CIAM (Congrés Internationaux d'Architecture Moderne). They also integrated Team X, a group of young architects charged with the organization of CIAM 10 in Dubrovnik 1956. Moreover, the Smithsons joined the Independent Group (IG), a collective of artists seeking a new aesthetics through modern objects as-found and popular culture. By 1955, they were associated with an architectural movement, Brutalism (Smithson and Smithson 1953).
Their most radical concepts would often be presented in unbuilt city schemes. Streets-in-the-sky were among the new urban structures envisioned by them consisting in wide galleries accommodating terraces, providing horizontal access to flats and linking buildings into a pedestrian net detached from traffic infrastructure (on ground-level). Although they lost the Golden Lane competition, their idea generated a serious following, especially in council housing. Park Hill  in Sheffield by Jack Lynn (1926 and Ivor Smith  was the first large-scale experiment with streets-in-the-sky linking several highdensity slabs. Streets-in-the-sky were drawn from deck-access collective housing. Examples like Page Street Housing  in Westminster (London), St. Andrew's Gardens , Myrtle Gardens (1936-37) and Caryl Gardens in Liverpool (1936-37) or Quarry Hill (1938) in Leeds had been designed to rehouse slumdwellers, inspired by Karl Ehn's Karl- Marx-Hof (1927-30) (see Figure 1) in Vienna (Boughton 2018), but the Smithsons do not see decks in such a straight forward way.
Urban structure-patterns of land use, infrastructure, and elements within a city-is discussed by the Smithsons in terms of human association and identity, and integrates concerns such as growth, mobility, and scale (Smithson and Smithson 1967), interests also held by other 1960s urban researchers. For example those of the Land Use and Built Form Studies (LUBFS) directed by Leslie Martin (1908-1999) and Lionel March (1934, which studied urban structure and typologies in the social and building sciences (Steadman 2016); the National Board of Public Building, which studied housing and urban structure in Sweden (Rosenberg 2012); but also Urban Metabolism studies, which embracing industrial engineering fields, have dedicated their attention to the functioning of flows over the urban and territorial domains (Wolman 1965); or even the lessons of vernacular architecture for contemporary urban form, as that conducted by the Portuguese architects in the Inquérito à Arquitectura Popular Portuguesa (1955)(1956)(1957)(1958)(1959)(1960)(1961) (Marat-Mendes and Cabrita 2015), a model also explored by Greek architects (Dimistantou-Kremesi and Marat-Mendes 2012), among others. It is significant that a lot of these inquiry fields seek to establish specific local conditions while framing them in wider cultural sets. The importance of local conditions was concomitant with the momentum gained by ideas around culture and society with the rise of sociology and anthropology. Some of the most important examples are Ruth Benedict (1887Benedict ( -1948 who studied cultures as integrated patterns knitting ideas, institutions, behaviors, representations and practices (Benedict 1934); or Howard W. Odum (1884Odum ( -1954 whose folk sociology understood society as being constituted by a series of integrated and interrelated concepts and processes (Odum 1953).
Only in 1963, the Smithsons got a social housing project, that would turn into Robin Hood Gardens. It reassesses the Smithsons' earlier ideas, including streets-in-the-sky, patterns of association and the relation of identity to the environment. However, left to neglect, Robin Hood Gardens is a story of annihilation. The western slab was demolished in early 2018 and the eastern one will follow soon, demanding, therefore, a reassessment of the Smithsons' work and of the wider culture they took part in the urban structuring for a democratic and socially integrated city.
Within the work of the Smithsons, streets-in-thesky go through four stages, which can be marked by four projects, namely Golden Lane housing estate and subsequent cluster city, the Berlin Hauptstadt urban project (1957) and Robin Hood Gardens. These moments, which we will discuss, were generally unbuilt or unpopular (Higgot 2007, 112), and even the small-scale experiment of Robin Hood Gardens was killed hastily by the anathemas of unemployment and social exclusion. Here, we submit that despite their problematic relation to contemporary urban policies, estates like Robin Hood Gardens and Park Hill could still be privileged spaces for resistance against such policies. We focus our analysis on streets-in-the-sky as elements of urban form, territorial forms that contribute to the modulation of the physical form of Human-occupied territory that bear witness to its built environment and its physical and natural needs (Marat-Mendes et al. 2014, 57) and present some potential advantages in terms of public space, community activities, pedestrian mobility, but also in terms of their environmental advantages.
To reflect upon streets-in-the-sky, we start by examining how the Smithsons' ideas have been interpreted, in academic and critical writing, in architecture and the visual arts. We then proceed with the analysis of three case studies: the unbuilt Golden Lane scheme, Park Hill (Sheffield) and Robin Hood Gardens (Poplar, London). These case studies are selective but range from the Smithsons' utopian vision to a critical appropriation by others and back to the Smithsons in critical reappraisal. We will draw from ideas expressed by the architects themselves, but also by pointing out the context in which their designs were presented. Afterward, a comparative reading is provided, in two timeframes (and two sections). First from their conception to the 1980s, when Margaret Thatcher's "Right to Buy" legislation suffocated the 1950s and 1960s optimism over council housing (Malpass 2005) and inhibited the experimentation of urban forms beyond those of modernist planning (Higgot 2007). In a second moment, we bring the streets-in-the-sky concept and other urban form solutions identified in the case studies, under a more contemporary analysis, focusing on political, ecological, and aesthetic concerns over current urban dynamics. We will focus on their features as a democratic element of urban form and explore what particular forms of engagement and occupation streetsin-the-sky allow. The visual arts are important in this discussion, since their use of these estates and the resulting imagery allows unique insights not only on how these buildings can be perceived but also how they can be transformed. Furthermore, these representations are highly suggestive in their depiction and creative use of urban landscape aesthetics (Gandy 2011) but also in consolidating ideas and values that, in the words of Higgot (2007, 7) become architecture.
The Smithsons and streets-in-the-sky: a brief retrospect The Smithsons were aware of the political aspect of their work, as testified in articles, essays, notes, and books published throughout their career. These are the best point of departure to study their urban vision. Streets-in -the-sky are explained in "Urban Structuring" (1967), "Ordinariness and light" (1973), and the doublevolume "The Charged Void" (2002,2005). Golden Lane was published in "Architectural Review" (AR), as an estate in 1955 and five years later as a Cluster City (Banham 1955;Smithson and Smithson 1957).
When streets-in-the-sky were first implemented, in Park Hill, Reyner Banham (1922Banham ( -1988 enthusiastically saluted the estate in AR (Banham 1961), noticing the implications of deck-access and the influence of the Smithsons. AD and the RIBA Journal both dedicated issues to Park Hill (Sept 1961 andDec 1962 respectively). In 1965, the Sheffield Council released a book celebrating Lewis Womersley's (1910Womersley's ( -1990 tenure as City Architect: Park Hill is the most celebrated example of post-slum Sheffield (Sheffield City Architect's Department 1962). It is featured on the first episode of the documentary series "Romancing the Stone" (2009) and in Michael Collins' "The Great Estate: The rise and fall of the council house" (2012). Owen Hatherley (2014) discusses Park Hill on his mapping of new ruins of Great Britain. In 2017, director John Cameron Mitchell chose Park Hill for some outstandingly aesthetic scenes in "How to talk to girls at parties".
With respect to Robin Hood Gardens, it was reviewed by Peter Eisenman in 1972 in AD. B.S. Johnson directed a documentary-interview on it, "The Smithsons on Housing" (1970). Martin Ginestié directed the short film "Robin Hood Gardens (Or Every Brutalist Structure for Itself)" (2009) dedicated to its recent history. Alan Powers edited "Re-Visions" (2010) the most important monograph so far. "The Great Estate" also discusses Robin Hood Gardens, stressing the polarizing opinions on the estate. BBC police drama "Luther" filmed one episode in the estate (2013). Another short film, "Streets in the sky" (2015) by Joe Gilbert shows the building's present-day melancholia. It was also the setting for a photoshoot by Lola Paprocka (clothes by Jessica Santini) for Vogue Italia (2017). Finally, the demolition propelled an exhibition in the Venice Biennale 2018, with a fragment of Robin Hood Gardens purchased by Victoria & Albert Museum.
We believe the inclusion of representations of the estates shows their aesthetic, cultural, and specifically cinematic value, which deserves further studying. Higgot has discussed how representation of and discourse on architecture has played a central role in how we perceive and understand buildings, namely that the context of ideology provides the field from which the building emerges, and publications may determine just how architecture is understood and also shape architects' actions as designers (Higgot 2007, 16). Here, we will observe some publications and the way they have represented the analyzed estates. However, it is in cinema and television that we will focus our commentaries on representation because in these media, buildings do not only get shown, they are engaged in a process of storytelling and image-making. We want to understand what images have been retrieved from these buildings, especially in the recent past and the present.
As for the Smithsons, their work was studied in depth by Van Den Heuvel (2013, who together with Risselada also organized the anthology "From the House of the Future to a house of today" (Van Den Heuvel and Risselada 2004). Webster 1997 has organized another anthology, "Modernism without rhetoric" reassessing part of the Smithsons' work. However, streets-in-the-sky have not been discussed in any recent scholarly work. In a report by geographer and reactionary ideologue Alice Coleman on council housing, deck-access is marked unacceptable (Coleman 1990). Yet, the scientific rigor of Coleman's assessments has been questioned (Hatherley 2014;Cupers 2017), while studies of urban form have evolved so that many of her arguments would be now tentative at best.
Undoing preconceived notions on social housing means reassessing its full vision and how it was (or rather was not) carried afterward. The influence of the Smithsons is outstanding in the 1960s and both Park Hill and Robin Hood Gardens are only examples-very different ones-of the struggle for a democratic urbanism beyond the physical, political, and cultural traumas of WW2 (Cunha Borges 2017).

Golden Lane as a democratic city
The Golden Lane housing estate competition ran from July 1951 until January 1952 (City of London Corporation 2013). Two-and three-bedroom flats, adequate daylight and ventilation, drying rooms, balconies, central heating, hot water, a basement store, bicycle access, large lifts, a community center, and a children's playground were required for the blitzed northern end of Central London (City of London Corporation 2013). Out of 177 designs, the winner was Geoffry Powell , architect and lecturer at Kingston School of Art College (City of London Corporation 2013).
Powell joined Joe Chamberlin (1919-1978) and Christoph Bon (1921-1999 to carry the project. After several alterations, the design by Chamberlin, Powell & Bon (see Figure 2) sets a tone for London housing, close to New Empiricism, promoted by Pevsner's AR (Van Den Heuvel 2013). International Style aesthetics were dissolved in widely appreciated English imagery like picturesque and Arts & Crafts (Banham 1966). Golden Lane is nicely delivered, but lacking in radicalism, in the line of Alton East  in Roehampton or the Lordship Lane Estate in Dulwich .
The Smithsons also submitted a proposal, distant from New Empiricism aesthetics. Theirs was a critique of Le Corbusier's Unité d 'Habitation in Marseilles (1947-52) and of the Chartre d'Athénes (1934). It presupposed a complex urban structure: dwelling units, public space, circulation, articulated into a pattern of mobility and identity (Smithson and Smithson 1967).
The structuring of Golden Lane aimed to create a true street-in-the-air, each "street" having a large number of people dependent on it for access (Smithson and Smithson 2002, 86). Unlike galleries of the 1930s, which were rather pragmatic and narrow, streets-in-the -sky were poetically charged, created for public enjoyment, wide enough for two mothers with prams to stop and talk and still leave room to pass (Smithson and Smithson 1967, 25). This marks the Smithsons' first attempt to change collective living: instead of one service interior street, like in Marseille, Golden Lane incepts a public or semipublic set of places (the decks) in which housing and other activities are present, but whose most outstanding effect is to detach motorways from pedestrian circulation (See Figure 3). As such, in this first phase, streets-in-the-sky are not just an access structure, they already suggest a deeper urban consequence. Each one is to form and develop according to particular needs. As they would often do in their speculative and built projects, the Smithsons create a building that is a sort of strange entity adding something to the city. In this case, a simple circulation system in which people can move easily without dealing with the much more complicated process of implementing a motorway framed by sidewalks and crossings.
Streets-in-the-sky are placed every third floor, with two-storey flats organized through a scheme of standard units with additional bedrooms, as needed. The entrance is at the deck level, with bedrooms and a bathroom. The kitchen, living-room, and larger bedroom are placed above or below deck level. The layout presented a central ax subdivided by two perpendicular axes, so density was balanced in each street-in-the-sky, variation remaining structurally possible. Subdivisions create groups of 12 flats, articulated in five groups, as the Smithsons believed that Forty or fifty houses make a good street (Smithson and Smithson 2005, 24). An important element is the garden adjacent to the kitchen, allowing an ambiguous double entry. This element was drawn from individual housing but denied private space as determining of exterior and interior, ambiguously welding house and city through a mobility structure. Van Den Heuvel notices that this garden allowed appropriation by the inhabitants: one could add extra bedrooms,  a place for housework, a houseshop, or simply enjoy it as a large outdoor space (Van Den Heuvel 2013, 264). But one could go further and suggest that the Smithsons are actively seeking to design a place meant for the housing unit-as the realm of the individual or the family-and the city-the public realm-to come together. Maretto says that the transition from the individual (a person or a family) to the civitas is far from obvious and often requires an intermediate stage for collective identification, which is exactly what the neighborhood is (Maretto 2018, 250). In the case of the Smithsons, not just the neighborhood structure proposed by the estate design, but the inclusion of streets-in-the-sky, provide this immediately recognizable intermediate stage. Furthermore, when accounting for the overall work of the Smithsons, Higgot (2007, 112) directly refers to it as an urban morphology, inviting us to see it as an urban form exercise, which goes beyond the models inspired from the Karl-Marx-Hof.
Given its structural organization and propensity to modular repetition, the estate suggests further extensions through decks. As pedestrian and automobile circulation were separated, two overlapping urban geographies can be imagined. That was how the Smithsons redesigned it after losing the competition. In CIAM 9, in Aix-en-Provence 1953, they presented Golden Lane not as a housing estate, but as a multi-level city with residential streets-in-the-air (Smithson and Smithson 1967, 22), their first vision of what could be a clustered city. This shift seems little surprising, since the original design was already a call-to-arms for a new urbanism, acceptant of modernity but skeptical of dogmatic or rationalist conventions. Remaining true to the estate design, the Golden Lane Cluster City has streets-in-the-sky linked together in a multi-level continuous complex (Smithson and Smithson 1967, 26). Other Cluster Cities advanced by the Smithsons are an extension of the radical urban vision started with Golden Lane: a close knit, complicated, often moving aggregation, but an aggregation with a distinct structure […] In the Cluster concept there is not one "centre" but many (Smithson and Smithson 1957, 334-336).
Orthogonality gives way to a twig-shaped layout, sprawling around different occupation patterns. Scale, density, mobility: all of these elements were posed in the estate design but were taken to their ultimate consequences in subsequent urban projects. The sprawling twig arrangement is significant: as mobility infrastructures, streets-in-the-sky integrating several buildings rely on local definitions of mobility and growth, by implementing more decks. Housing acquires foundational value in the Smithsons' modern city, functionally and symbolically cohering new and preexisting urban areas.
Another important aspect was the use of raw concrete as found, an aesthetic element itself, with a pop monumentality turning sci-fi hyperbole into density-controlled linked units (Banham 1966). For the Smithsons, local scales incite identity and creativity within communities inhabiting urban clusters (Smithson and Smithson 1967).
The type-structures introduced by Golden Lane are conceptual models for growth and adaptation. Hence, the layouts of buildings and walkways are geometric but not rationalist. The ambiguously telluric geometry of the Cluster Cities envisions urbanism beyond modernism. The twigs are physical manifestations of relationships between buildings, functions, and accesses, which sum up to relationships between people both as scaled groups and individuals. In its imagery and ambition, disseminating through the ground, Golden Lane predates geometrical psychedelia films like "The trip" (1967) by Roger Corman (b.1926), "2001: A Space Odyssey" (1968) by Stanley Kubrick (1928Kubrick ( -1999 or "Fantasy" (1976) by Vince Collins (b.1944). Incorporating raw materials in emotionally charged forms, Golden Lane predates the melancholic post-punk and industrial sensibility of Joy Division (1976)(1977)(1978)(1979)(1980) and Nine Inch Nails (1988present). This parallel is thought-provoking, since some of them have reached cult-status, leaving one to wonder why the Smithsons' urban aesthetics have not enjoyed a similar reputation.
The intricacy and sparkle of Golden Lane are visible in the images presented at CIAM. Alison Smithson's photomontage shows the superstructure erupting from Coventry. Van Den Heuvel states that it is as if the new architecture is not simply going to replace the old society, it is projected onto the ruins enjoying its own liberated, autonomous geometry, the very distance between the two worlds acting as a generative principle (Van Den Heuvel 2013, 69). Golden Lane's monumentality does not annihilate the city, it rater makes it cohere in unexpected ways. Inhabited by pop characters, the photomontages of Golden Lane mark its Romantic idealization of a modern world.

Urban projects and Park Hill
CIAM 10 was held in Dubrovnik in 1956 and organized by Team X, based on their 1954 Doorn Manifesto. The need for local discussions overwhelmingly superseded prewar functionalist methodologies as the human complexity of cities seemed incompatible with the rigidity of Chartre d'Athénes urbanism (Mumford 2000).
In the Manifesto, the Valley Section of Patrick Geddes was redrawn into four scales of association. Communities structured with specific patterns and varying densities were distributed along a valley of settlement scales, similar in thought to Geddes' studies of physical and social territories (Figure 4). The Smithsons designed one cluster for each scale: Galleon cottages, Fold Houses, Close Houses, and Terraced Crescents, respectively, for isolate, village, town, and city scales. Different patterns of association, mobility, traffic, and typology were explored in each type of settlement (Smithson and Smithson 2005).
Later, in Berlin Hauptstadt, the architects propose a regular grid of motorways detached from a second infrastructure: streets-in-the-sky linking buildings of different densities and functions. This multi-level urban project no longer depends on built masses. A web of walkways is designed to face mobility demands, and while it suggests the implementation of specific buildings, it, more importantly, creates a rule, a form of physical aggregation between buildings and mobility structures. In here, streets-in-the-sky are not just an articulation between the individual house and the city, but a central and sui-generis element of the city itself, which implements a new form of circulating and a totally new urban landscape, rhythmed by individual movement, rather than articulation with motor-traffic. This is also an important time for the debates on Brutalism. The first notion-"warehouse aesthetics"was advanced by the Smithsons in 1952, and Reyner Banham's manifesto-essay followed in 1955. After Banham's later book "The New Brutalism: Ethic or Aesthetic?" (1966), it became clear that it escaped onesided descriptions. The Smithsons and Banham agreed there were ethical and aesthetic implications to Brutalism (Van Den Heuvel 2015). Memorability as image, materials as-found and structural clarity-reclaimed by Banham (1955)-as well as connectivity, association in an urban context and "raw" qualities (Van Den Heuvel 2015)-advanced by the Smithsons-are basic features we now associate with it.
In 1961, Banham reviewed the Park Hill estate in Sheffield, the first large-scale experiment with streets-inthe-sky (see Figure 5). This portentous council estate is often seen as one fundamental example of Brutalism, and rightly so. It uses the Smithsons' ideas directly. Former students of Peter Smithson, Lynn, and Smith, the authors of the estate, were seeking alternative solutions to both the Unité and tower blocks (Lynn 1962, 447).
From their studies for mass production techniques and metropolitan redevelopment (Lynn 1962, 448), streets-inthe-sky were ultimately chosen for Sheffield Valley, after slum-clearance. Through these deck-streets, Park Hill oversteps the formal limits of the Unité towards a scheme closer to the Smithsons. Lynn and Smith start from a family of house plans (Lynn 1962, 452) and structural solutions-stairwell towers, corner flats, bridges and meeting points of building and slope. These integrated elements ensure the visual, formal, and structural unity throughout site-specific conditions.
The slabs seem to be recoiled from a tense center, successively relaxing and enlarging. Park Hill is emphatically temperamental and, as Banham suggests, anticlassical (Banham 1961, 410). Despite the detachment of the ironic and obsessive bending, Park Hill must be seen as Banham suggests: a building with two main façades and five ends (Banham 1961, 413). On the other hand, by celebrating the repetitive aesthetics of such a monumental scale, Park Hill allows for structured appropriation, a theme discussed in the Smithsons' early writings for its radical urban implications: similar spaces would be individualized and "imprinted" by inhabitants,  to express their presence, their occupation of a place (Smithson and Smithson 1967).
Streets-in-the-sky organize the blocks around social spaces, an infrastructural network connected with several points of urban interest. Like the Unité and Golden Lane, dwellings are two-storey, organized around an H knot of stair-walls. Entrance is at decklevel to one-bedroom and two-bedroom apartments, and two-bedroom and three-bedroom maisonettes. Toilets and kitchens are placed on the center of the flat, bedrooms, and living rooms at the façades. Despite the wide decks, the lack of terraces feels poorer than the idealization of the Smithsons.
In 2014, director John Cameron Mitchell chose Park Hill to be the central space of his film "How to talk to girls at parties", a sparking and over-the-top metaphorical recreation of the punk movement, which in Britain was often associated with council housing (Stone 2014;Cunha Borges 2018). In the film, most of the sights of Park Hill are associated with freedom. A walkway linking two slabs is used by the protagonist, Enn (Alex Sharp) and his friends as an outdoor living room. When Enn falls in love with Zan (Elle Fanning), Park Hill's streets-in-the-sky are the place where they take walks, ride a bike and talk about "the punk", to use the film's expression. (See Figure 6).
As a project, Park Hill is an interpretation of Golden Lane, the Cluster City, rather than the estate project. Despite fundamental differences between the Smithsons' design and Lynn's and Smith's-least of all in the dwellings-Park Hill deploys a network of streetsin-the-sky performing as the Smithsons' intended. And while this network never expanded beyond the estate, it confirmed streets-in-the-sky as urban structure, enough that many council architects started experimenting with them. The early enthusiasm over Park Hill was fundamental for the interest in the Smithsons' ideas. Other examples are Hyde Park (1962-65) by Lynn and Smith and Kelvin Flats (1965-66)    or the Otterburn and Eden Closes (1967-71) by J. Austen Bent  in Manchester.

Liberated places: Robin Hood Gardens
Robin Hood Gardens was born from a 1962-64 project of the Smithsons for Manisty Street, whose famous axonometric shows a critical return to roots. Residents' protests led to a restructuring by the Greater London Council (GLC) and turned into the Robin Hood Gardens estate (Smithson and Smithson 2002, 297), finished in the 20th anniversary of Golden Lane: the Smithsons' first radical urban project goes full circle.
As Risselada says, critical projects for postwar reconstruction were only put to build form in the 1960s, under the contradictions of a centralized welfare state (Risselada 2005, 164). This unease is clear in the ambiguous relation Robin Hood Gardens establishes with middle-class values, identified by Peter Eisenman's review (1972) which falls short of favorable.
Eisenman shows an incomplete understanding of the Smithsons' approach to a middle-class lifestyle. Where he sees them caving to its self-evident proliferation, there may be a conspicuous restatement of previous beliefs. In 1967, they wrote an article on "Criteria for mass housing" (Smithson and Smithson 1967a), enlisting important aspects, including adaptation to lifestyles, expression of identity, integration of technical elements and construction technologies, articulation of visual structure and function, open-air areas linked with inside areas, enjoyment of weather changes, spaces for children and storage, maintenance, and implications of repetition (Smithson and Smithson 1967a, 393). The concern for the social qualities of the estate is described here in terms much more precise than in the 1950s, a clear effect of dealing with municipal limitations. But it is remarkable that the criteria still builds up to a set of concerns that remains entirely committed to the same core values, implementing housing needs into a "communitarian" scheme, with deck-streets still useful for conviviality. These ideas were fundamental for Robin Hood Gardens and could be read as a manifesto. Streets-in-the-sky are important despite the budget cuts that downsized their width, as they implement common areas and circulation places (instead of passages) encouraging neighbors contact (Hatherley 2012, 28), which we believe could even increase through a refurbishing of the estate and its outside areas.
The bent forms layout was demanded by the GLC, although it matched the Smithsons' instinctive attempt to make spaces "which seem to offer escapes" (Smithson 1971, 481). There is no unifying superstructure and the entrance gardens of dwellings were beyond financial Figure 6. Park Hill street-in-the-sky-snapshot from "How to talk to girls at parties" (2014) by John Cameron Mitchell. Available at https://a24films.com/films/how-to-talk-to-girls-at -parties.
resources, but Robin Hood Gardens still incorporates essential Golden Lane concepts.
Formally, it reinvents the visual structure of its sideroads while resisting organicism. Curves are reshaped, mediating between the circular elements on the garden and the geometric complexity of the slabs. (See Figure 7). Façades are structured by repeating concrete mullions, rendering the identity of the building perceivable from any point, as Peter Smithson stated, so that repetition in a mechanical sense seems melted away (Smithson 1971, 481). The slabs have great emotional breadth, turning the road forms into a visually dramatic interplay of solid monumentality and void. There is an immediate iconic value to the estate since slabs are dynamically linked but disconnected. (See Figure 8) Unlike Webster, we do not believe this is a literal transposition of a form first proposed in 1952 (Webster 1997, 73). The return to heroic Brutalist imagery Webster identifies rather shows a progression in the Smithsons' aesthetic sensibility: next to orthogonal Golden Lane, Robin Hood Gardens has a mannerist overtone visible even now during the building's decay.
Streets-in-the-sky are built with high-quality concrete and glass plans (see Figure 9). Dwellings are linked to the deck by an entrance niche, recycled from the 1956 Close Houses. (See Figure 10) In the inner façades, blue metal plans separate the balconies, with concrete mullions again showing flat limits. In direct confrontation, slabs recognize each other with instant familiarity but not total identification. The lift-towers mark the northern ends, widening to fluid 70 degrees diagonal stylet-like balconies, marking storey-distribution and the position of decks.
Housing units are predominantly three-and fourbedroom flats. The three-bedroom is entered at deck level, with a kitchen and a bedroom plus two bedrooms and a living room above or below the deck. The fourbedroom has a kitchen at deck-level, with four rooms and the living room above or below deck level. Flats are not especially big, especially with the smaller flats, but all of them have greater areas than those suggested in the 1961 Parker Morris Report which was standard at the time. It would probably be exaggerated to state they lack quality (Eisenman 1972, 590).
The positioning of flats is perhaps too strict: streets-in -the-sky are only overseen by entrance halls, with kitchen and bedroom windows opening to the garden, while living rooms and the fourth bedroom have windows to the outer streets. As such, streets-in-the-sky are barely within eye's reach from inside, although this also allows privacy in all of the flat. And whatever the case, that does not seem to have made them less lively during the day (Hatherley 2012, 28). Moreover, Eisenman (1972, 590)    points out that while the public domain is full of imagery, the private units seem devoid of anything other than the mechanics of living in the present. Yet "living in the present" was something the Smithsons always celebrated-hence their interest in advertising (Smithson and Smithson 1972). More importantly, Robin Hood Gardens' use of precast concrete and standard construction is not "mechanic" but brashly as-found. The estate is indeed more impressive on the outside, although flats have a coherent and slightly pop lexicon, discreet but sophisticated, providing plenty of opportunities for appropriation.

From innocence to experience
Poet William Blake (1757-1827) famously wrote on the relationship between innocence and experience. The "Songs of Innocence" (1789) are answered by the "Songs of Experience" (1789-94): the self is ravaged and divided (Paglia 1990). We believe that a similar process can be witnessed within the social housing as influenced by the Smithsons.
Robin Hood Gardens prioritizes housing and association, with a liberated garden defining the scheme. This public space counters the pressure of Poplar High Street and Blackwall Tunnel. Eisenman (1972, 558) sees a motorway preponderance, but his interpretation is muddled. Although in Golden Lane buildings are in themselves fragments of a larger scheme (Eisenman 1972, 558) it is less certain that in Robin Hood Gardens the built form negates the idea of an accumulative empirical process and accepts the present context (Eisenman 1972, 558). The estate creates a new pattern of settlement, turning motorway occupation against itself. Eisenman seems rushed in claiming slabs are not intended to be conceptually continuous (…) indicating a termination and no future connection (Eisenman 1972, 590). In Park Hill, slabs are also designed with relative independence, despite the continuous streets-in -the-sky. A growth in similar terms would be possible in Robin Hood Gardens. The Smithsons were not strangers to aesthetic of connectivity in isolation (Smithson 1975, 347) as in the sketches of Golden Lane clusters, ideograms for Ministry buildings in Berlin Hauptstadt, the Arno Centre in the Florence study (Smithson and Smithson 2005), but mostly the sketch for Robin Hood Gardens growth, confirming the Smithsons' notion that the building today is only interesting if it is more than itself; if it charges the space around it with connective possibilities (Smithson and Smithson 1972, 36).
Evidently lacking the thickness of the Golden Lane drawings, schemes, photomontages and essays, this sketch by Peter Smithson (Figure 11) still gives a sense of how the architects idealized urban growth in this particular project, through linked gardens delimited by formally coherent slabs. Pedestrian circulation becomes secondary, perhaps less an acceptance of the generalization of car-use than a restatement of the purpose of clusters: Creating new images, both for the new elements themselves and for the old elements which they have transformed (Smithson and Smithson 1957, 336). London's structure had been strongly marked by motorways and public spending decreased. Thus, the need for public areas is greater than in the 1950s. There is a shift  from streets-in-the-sky promoting movement and public activities, towards stress-free gardens suggesting no specific association but providing a portentous counterpart to busy street-life. The number and complexity of urban elements are overall bigger than Golden Lane, making Eisenman's indictment of conformity less probable.
Streets-in-the-sky loose part of their radicalism when enclosed for the building, as in Robin Hood Gardens. Banham (1966, 42) suggested street-deck held together serial compositions, but continuity proved less obvious after the 1950s: it would make little sense in Poplar to prioritize gardens and still conceive streets-in-the-sky with the same public emphasis of Golden Lane. The ground level has a very pronounced significance in Robin Hood Gardens, compared with Park Hill where the relation of continuous streets-in-the-sky to the ground-floor is less clear, but the former have greater independence.
Golden Lane revised the urban implications of collective housing and motorway circulation. The latter had been generally conservative in Marseilles, as the Unité was a block within a garden that has eventually turned into a parking area, establishing no concrete links to the surrounding area. The interior street likewise has no particular relation with the territory, and even Banham (1966, 88) concedes that streets-in-thesky were originally Brutalist, not rooted in Modernism. The classical geometry of Marseilles is the last thing on one's mind in Park Hill, formally more dramatic than the Smithsons' Golden Lane, and despite the complex grids in the façades, all these designs explore industrial aesthetics unseen in Le Corbusier. Already in the Golden Lane megacomplex, it is clear the contained and rationalist Unité is unsuited for metropolitan scale. Park Hill confirmed this vision, communitybased but monumental, without the Unité's apologetic self-contention. It is an ambitious estate, actively changing territorial and living patterns and connecting different areas, generating diverse spaces and forms.
Visual reflections and subversions in Robin Hood Gardens propose an urban vision unattainable for the rationalist mind, but impressive and moving for those who enjoy specifically urban imagery. We believe that the saddest aspect of the estate is that it shows the Smithsons trying to fight realpolitik, with budget-cuts dictating many features-like stairwell and deck widths-that facilitated demolition. The ravaging of experience came to knock down the innocence of the Smithsons' original vision.
With respect to streets-in-the-sky, they were not demised by chance. At least in England, they were caught in Thatcher's welfare state downsizing: her "Right to buy" legislation privatized a considerable part of the State's housing stock (Malpass 2005). The collapse of Ronan Point in London, 1968, led to the discovery of construction faults in many estates. But it was a report by Alice Coleman, Thatcher's right hand for housing policies, that determined the fate of council housing (Cupers 2017, 178). Despite Coleman's commitment to factual evidence and firm foundation of truth (Coleman 1990, 1), Hatherley (2014, 94) points out graphics in her research are pseudo-scientific, while Cupers (2017) argued she merely adapts Oscar Newman's defensible space (enclosure of space to ensure defensibility) to England. Her attack on highrise buildings revolved around criminality. Interestingly, social conditions within estates were ignored-as pointed by Newman himself (1987, 30). Coleman writes as if design determines behavior. Yet, studies on urban form have shown that the relation of behavior to urban form is less clear than its relation to socio-economic traits (Lo 2016;Habraken 2009). This hypothesis is carefully unexplored in Coleman's biased report.
Streets-in-the-sky, unpoetically called overhead walkways are criticized for the degree of anonymity experienced, and also in the number of alternative escape routes (Coleman 1990, 36-38). Indeed, they were meant to liberate mobility, but Coleman sees a different problem: that this will also serve the thief and the rioter.
Streets-in-the-sky suggest rather large horizontal schemes as Park Hill and Robin Hood Gardens. Coleman disliked high-rise buildings, but large horizontal estates were equally problematic, since anonymity feeds on size (Coleman 1990, 15). Yet Coleman's argument fails to be realistic: her defense of private lowdensity housing is conveniently oblivious to the fact that urban population tends to grow, not decrease, and that there was never a consensus in the adequate size of urban forms. Among others, Arnis Siksna, Barry Maitland, Ernie Scoffham and Anne Vernez Moudon have argued that large blocks are more appropriate to accommodate specific activities, such as commercial and mixed ones, throughout the promotion of new galleries and inner routes, especially where intensification and change is predicted (Marat-Mendes 2002), as it happened in London. Marat-Mendes (2002) has also pointed out that small blocks do prevent physical change to occur while ensuring stronger changes in uses and functions.
Coleman hastily identifies Ebenezer Howard's Garden City (1898) and Le Corbusier's Radiant City (1923) as roots for postwar planning and criticizes those models for being based upon intuitive beliefs and prejudices (Coleman 1990, 7). This critique could be turned against Coleman herself: despite her misrepresentation of statistical provocation as scientific inquiry, Coleman's greatest flaw is her unrealistic vision of urban fabrics made of townhouses and cottages in lowdensity neighborhoods. This is the perfect scenario for houses ready to be explored by the private market. But taking a walk in London would show why this is a dangerously reactionary urban vision.

Towards an "informed innocence"?
Park Hill is to be fully refurbished by Urban Splash, an urban development that was careful enough to deform the façades and turn the estate into upper-class fait-divers (Hatherley 2009), dried by the perverse rhetoric of the "creative city" in which sub and countercultural elements are turned to profit by investors (Mayer 2013, 11). Park Hill may still stand, but when the council offered (Hatherley 2014, 97) it to Urban Splash, it ceased to provide quality housing at council-controlled rents. Robin Hood Gardens is to be demolished and replaced by a "green development" which meshes a mild interpretation of New Empiricism with Ikea aesthetics to gather upper-class clientele too.
As neoliberalism solidifies, perhaps the greatest failure here was the establishment of a true democracy. Robberies and vandalism are possibilities for any space, in the sky or on the ground. Estates with individual houses and no overhead walkways are hot-spots of crime if they are inhabited by communities whose basic needs are neglected. A quick look at the terracedhousing Boot Estate in Liverpool (before refurbishing) shows this clearly. Good design always fails if the aimed living conditions cannot match. The problem was not that Utopian designs trapped people in houses not of their choosing, as Coleman (1990, 6) cynically affirms, but rather that people got trapped into estates which got removed from political interest, out of sync with a conservative culture where children must be taught to respect private property (Coleman 1990, 10) and the State does not trust citizens enough to hand them the management of their spaces. This intention was always present for the Smithsons, especially considering their concerns for identity and for freedom of movement, rather than its mechanization by architectural-or political-decision (Smithson and Smithson 1967).
Marat-Mendes synthesizes resilience as a balance between continuity and transformation (Marat-Mendes 2015, 133). Given their outcomes, it is impossible to confirm resilience in the estates discussed. However, we can assess how they could have performed if they were still integrally existing. Although cities are undergoing tremendous change, there remains a certainty, as Batty (2017) suggests, as to territorial equilibrium, despite the fact that people, behaviors, and perceptions shift faster than urban structure. The resilience of our urban systems is being put to the test, in both physical and political terms. Recent changes introduced by global urbanization and austerity (Mayer 2013) replaced the democratic city envisioned by the Smithsons and their interpreters with a neoliberal city of deregulation, strengthening of private markets, social inequality, mega-gentrification, consumerism, tourism, work-play, and enclosures (Mayer 2013, 9). Post-WW2 urban structuring is incompatible with these values. If these estates promoted permeable buildings that allowed one to move through urban space, we have long been accepting the downsides of our cardependency. While automobility allowed for outstanding personalization of mobility and a considerable economic development, it is also a system widely affected by sunk investments and public (self-)deceit, as well as little innovation and a delay in fulfilling its promises in many social groups (Kemp, Geels, and Dudley 2012). Furthermore, traffic problems worsen environmental and practical urban conditions (Kemp, Geels, and Dudley 2012). As housing towers became a common presence in urban landscapes, and most of us were educated to move on ground level or inside enclosed buildings, we easily accept to inhabit in height while refusing to walk in height.
Geels' work has recently been framed in the context of reflexive modernity (Spaargaren, Oosterveer, and Loeber 2012), since his analysis of the connections between niches, regimes, and landscapes is closely related to a "reflexive" second modernity, in which the nation-state as the central political organizer, the clear distinction between society and nature and the relations between scientific knowledge and beliefs have all gone under violent criticism and ultimately dismissal. Estates like Robin Hood Gardens and Park Hill are the spawns of serious-though sometimes intuitive-concern for collective space, though not from the perspective of leisure, but as urban elements for the community to use according to their own interests or needs. As such, many forms of urban activism (Mayer 2013) could find in these estates a means and a symbol for their struggles. Higgot (2007, 16) states that ideologies provide a field from which architectural practice emerges, and we would further suggest that ulterior ideologies provide a field from which architectural examples can be reinvented. This possibility can be particularly important for urban activism.
Neoliberalism, an adverse effect of some conditions of reflexive modernity, is even less sympathetic to the Smithsons' "innocence" than their own time. But while their experimentalism sounds more utopian Powers (2010), Van Den Akker (2010, 2015) have identified a resurgence of the figure of Utopia in metamodernist sensibility, where utopia is a tool rather than an ideological blueprint (Vermeulen and Van Den Akker 2015, 65). This framework allows a revaluation of their ideas towards a sort of "informed innocence"informed by struggles in the creation of commons and sustainable urban environments, without losing sight of radical visions for our cities. We would point out several missed opportunities for resilience in terms of politics and sustainability for these estates.
Both schemes-from their inspiration in the Smithsons' Golden Lane-are designed with large public areas we can call urban commons: commonpool resources difficult for economic transaction and publicly used, including parks and community gardens (Parker and Schmidt 2017). Both estates were handed to private companies, therefore testifying how commons are under (continuous) attack. In these cases, although residents have not always perceived green-fields as commons, they were never given opportunity or encouragement to do so. If Vrasti andDayal (2016, 1001) describe commons as the wealth we own in common and the power to create and control these "things" collectively, they also analyzed frailties in access and participation, especially towards excluded groups. Privatizing these estates confirms this rule, but uncomfortably perverts their original intents.
As urban agriculture and Guerrilla Gardening (Reynolds 2016) movements continue to grow, the green-fields in these estates would have proven of great potential for resilience, since none were planned for agricultural activities, but both were designed with resident appropriation in mind (Smithson and Smithson 1972aa;Lynn 1962;Marat-Mendes and Cunha Borges 2017). Urban agriculture has environmental benefits and provides a means for community bonding over the sharing of experiences and knowledge (Cabannes and Raposo 2013), confirming the Smithsons' emphasis on the human association. Furthermore, urban agriculture allows for the creation of community-created "nutzgärten" or useful gardens (Reynolds 2016, 15), either part of Guerrilla Gardening movement or not, allowing people to appropriate public areas and turn them into productive spaces of great environmental potential (Wekerle and Classens 2015).
Although these are high-density estates, their typology might be described as serial compositions (Banham 1966, 42) or continuous complexes (Smithson and Smithson 1967, 26), horizontal, neither compact nor low-rise. Research has shown that compactation, a generalized planning strategy, has less environmental efficiency than previously thought: often, less housing options, crowding, and congestion are countered by only meager CO 2 reductions (Echenique et al. 2012, 136). Thomson and Newman (2017) have suggested that restricting the development of automobile urban fabric toward transit and walking fabrics while maximizing resource efficiency for transport fuel, solid waste, and building materials would amount to regenerative qualities in urban form.
Moreover, as opposed to the dependency of pedestrian routes with motorways, streets-in-the-sky as infrastructure would allow for close-distance mobility to be ensured by smaller and cheaper structures. These mobility patterns would change urban metabolism by reducing the stock of materials needed for close-distance circulation while decreasing car dependency and its CO 2 costs.
Finally, streets-in-the-sky reduce land-use intensity which has long-term effects on ecological systems; and even change land-cover patterns, fundamental for the environmental performance of soils with large-scale consequences (Erb et al. 2016). Streets-in-the-sky would allow for diversified site-specific pathways without actual coverage of soil and using a relatively reduced stock of materials.
These brief notes suggest how streets-in-the-sky may have political and sustainability advantages that supersede the Smithsons' original intentions. As Gandy urges sustainable urbanism to not lose its architectural nerve (Gandy 2011, 63), maybe these radical urban structures can provide an "informed innocence" to counteract neoliberalism drawing from a metamodern concept of utopia (Vermeulen and Van Den Akker 2010).

Closing remarks
BBC series "Luther" follows the life and work of maverick inspector John Luther (Idris Elba). One of his cases takes place in an East London estate. As a suspect tries to escape, Luther abruptly hangs him for a minute outside the street-deck. As quarters fall off his pocket, landing several feet below, one ironically feels the building would make his death darkly glamourous (Cross 2013). This scene was shot at Robin Hood Gardens. This could be a confirmation of Coleman's indictments of council housing, were it not for the countering scenes inside another suspect's cozy flat, and the outside plans showing the powerful imagery of the estate.
Soon, representations will be all that is left from the Smithsons' only built council estate. Demolition of the first slab started in August 2017 and finished roughly half a year later, while the second slab is scheduled for demolition in 2020. All campaigns to save the estate, as well as a survey that stated 80% of the residents preferred a refurbishing, failed to stop its destruction. However, discussion of it and its concepts must not cease. Ideas and urban structures must be seen in their historical context and also in the present. If Robin Hood Gardens is being destroyed now, it must have been deemed useless or unacceptable now. One should question why and identify the implications of this on the collective memory of urban form perception.
Park Hill, while preserved, has lost nearly all of its original character and is now just another lively and upper-class estate imbued in the spirit of redevelopment and gentrification. The raw quality of the slabs was replaced by shiny plastic surfaces that deprive the estate of its once rugged outlook. By the end of Mitchell's film, Elle Fanning has a very simple monologue looking over the nightlights in Park Hill streets-in-thesky. (See Figure 12) Fanning talks about a world that is far from perfect, but still good, still worth fighting for. Park Hill is not an estate, or "colony" to use the film's term, but civitas made into concrete. For all its raw and sometimes dirty aesthetics, Lynn's and Smith's design indeed defy us to look at is as no simple case. It encapsulates big dreams and hopeful visions of humanity and the world, but also the de facto messier reality of collective living. In the romantic and tragic scene where Mitchell's protagonist couple breaks up, Park Hill does not look like a concrete eyesore or a welfare state mastodon, but rather like a subtle and optimistic future city, one that conveys and celebrates the many. Its monumentality is epic but not oppressive.
The Smithsons (Smithson and Smithson, 2002, 296) stated: The theme of Robin Hood Gardens is protection. As one arrives, it feels like walking into an enshrined garden, a fluid tension between free-standing space and dense urban occupation. Do we now need urban spaces with this concept of protection? Can our cities benefit from urban structures that render protection spaces mobile and expansible?
Streets-in-the-sky were a sensible alternative to tower blocks without resorting to low density. Their collectivist overtones made them seductively democratic. Under neoliberalism, cities are dominated by real-estate interests that visibly harm the majority of the population. These dynamics are close to the 19th-century idea that the problems of the poor concern only the poor (Malpass 2005). Nowadays, the privileged groups in urban spaces are serviced by a struggling precariat (Standing 2011) and social relations deeply marked by inequality. In the words of Mayer, the struggles of all those excluded from the neoliberal city, be they at the peripheries of this model (in the banlieues and ghettos) or invisibly servicing the privileged users from subliminal and precarious spaces, will need to be connected (Mayer 2013, 13). We suggest that council housing and its heritage may be of special interesting in providing this connection between different urban struggles. For all their concerns over scale, mobility and public spaces, these estates envisioned above all a world of equal opportunities where presence (or occupation) is more important than ownership, where streets extend to the sky to allow the city to be walked and perceived from many points of view, multiplying the layers of passage and permanence, creating a culture of public commons (although the word was never used then). Crime and escape routes are a discourse born out of the political failure to achieve the best ideas emerging from the post-WW2 to the 1960s. More important than the Brutalist debate hereeven though Brutalism cannot help to be at its center-is the loss of a democratic aesthetics, one that connected people and places, one where the citizen was allowed everywhere because buildings are not barriers in the city, but rather connective and generative elements. The pathway for sustainability in social and environmental terms would be more ensured in these buildings than in many of the interventions planned to replace or reframe them. In the mediocre estate-with rents ranging from 510£ to 930£ (Blackwall Reach 2018)-that will replace the Smithsons', England's current housing shortage (Booth 2018) is far from priority.
Robin Hood Gardens is also the only estate designed by the Smithsons, and its demolition caused some malaise in architectural debates, unable to counter the indifference with which it was received in the 1970s. But its potential-and that of many other 1960s and 1970s estates-has grown, and it may now be clearer that in Robin Hood Gardens, the Smithsons remain radical and forward-thinking, democratic, critically modern and obsessively transformative. Furthermore, it exposes the potential that exploring new urban forms can have in the construction of a desirably democratic city. Now, no one will commit murder in Robin Hood Gardens by pushing someone out of the street-in-thesky. But the meaningful space within a busy urbanized area, the belief in a democratic aesthetics and the poetic longing for streets that run across a symbolic sky are lost as well. Typical of a society that tends to focus on destructive politics, Robin Hood Gardens is the first tragedy of 21st-century architectural history.

Notes on contributors
João Cunha Borges holds a MSc in Architecture (ISCTE-IUL, 2017). He works as a Researcher at Instituto Universitário de Lisboa ISCTE-IUL, DINÂMIA'CET. He wrote a dissertation on the work of Aldo Van Eyck and Alison and Peter Smithson, titled "The dissolution of the modern complex". His research seeks to contribute to a multidisciplinary approach to architectural theory, including Urban Planning History and Sustainability, Aesthetics, Anthropology of Space, Film History and Popular and Folk Culture. João currently works at the research project SPLACH -Spatial Planning for Change, which aims to inform a sustainable transition of the sociometabolism of Lisbon Metropolitan Area spatial planning.