By the early 1950s criticism of pre-war functionalism within the CIAM (Congrès Internationaux d'Architecture Moderne) - directed above all at the Athens Charter - became hard to ignore. The requirement that urban design separate the residential, work, recreation and traffic functions seemed to the younger generation of architects the root of all urban-design evil. Aldo van Eyck who worked together with Constant on various projects, summarized the criticism:

Instead of the unpleasantness of dirt and confusion, now we have to contend with the boredom of hygiene. The material slum has disappeared […], but what has taken its place? Miles upon miles of organized nowhere, and no-one has the feeling anymore of being someone who lives somewhere. (1)

Cover of Reynar Banham's ground-breaking Megastructure. Urban Futures of the Recent Past, London / New York 1976

At the ninth CIAM Congress in Aix-en-Provence the young rebels were commissioned to prepare the tenth and last. Out of this arose Team X, a coalition of architects which included Peter and Alison Smithson, Georges Candilis and Shadrach Woods, Jacob Bakema, and Aldo van Eyck. As Constant and Friedman, most of the Archigram members were in close contact with the Team X architects. But the megastructualists took the Team X ideas much further, designing urban visions characterized by mobility, flexibility and the participation of their inhabitants. With these designs they became the late heirs to a long tradition of idealist urban planning.

There seems to have been a remarkable lack of communication between the megastructuralists and the planners who actually built ideal cities in the 1960s: Le Corbusier (Chandigarh) and Oscar Niemeyer/ Lucio Costa (Brasila). This is all the more surprising as with his project for Algiers back in 1931 Le Corbusier had produced an urban design concept already displaying many of the characteristics of megastructure. His Projet‚ Á Fort l’Empereur represents a departure from the classical ideal city; instead of an urban structure with squares, streets and buildings, a continuous monument appears, a linear city which can be extended as required, snaking through the North African landscape. Up above, on top of the gigantic edifices, two-storey houses were to be built, fitted out according to their occupier’s wishes, not according to the architect’s plans.

Ralph Wilcoxon (College of Environmental Design, Berkeley) defined megastructure in 1968:

• constructed of modular units;

• capable of great or even ‘unlimited’ extension;

• a structural framework into which smaller structural units (for example, rooms, houses, or small buildings of other sorts) can be built, or even ‘plugged-in’ or ‘clipped-on’, after having been prefabricated elsewhere;

• a structural framework expected to have a useful life much longer than that of the smaller units which it might support.

Fundamental to megastructure is the separation of ‘hardware’, the constructing framework including the whole urban infrastructure such as energy supply, water and transport, from ‘software’, which can be slotted in or out of the supporting structure as required. The separation of the supporting structure from individual modules should enable the city to adapt without huge effort to its citizens’ individual wishes, as well as to the changing social and economic conditions. Architecture becomes mobile; architects can abdicate in favour of citizens and, as demanded by Yona Friedman, confine themselves to the role of technicians.

As well as Constant, Friedman, Archigram, many other architects and planners also count as megastructuralists, whose designs cannot be dealt with in detail in the exhibition. The most important are the English architect and theoretician Cedric Price and the Japanese Metabolists, along with designers like Frei Otto and Buckminster Fuller.

The megastructuralists’ urban visions were determined by ‘Möglichkeitsdenken’ (notions of possibility), boosted by the prosperous economy of the 1960s, suffused with a belief in the liberating power of automation. The plans can be seen to reflect the processes of social revolution sweeping through Europe in the 1960s as well as the predicted rapid population increase.

(1) In: Ruth Eaton, Ideal Cities: Utopianism and the (Un)built Environment, London 2002