Although this is under the aegis of the Hayward, it draws upon the collections of the Royal Institute of British Architects and the Victoria and Albert Museum, plus other contemporary material gathered specially. You get everything from a designs for a Tudor tower house (dated around 1500) to the computer game Sim City, which must surely inspire a whole new generation of masterplanners just as Meccano spawned high-tech. You get album-cover fantasy architecture (an imagined house on a mesa in the Arizona desert by architects ORA-ITO) and pop video and film-set architecture. You get some ingenious juxtapositions, such as artist Claes Oldenburg's "London Knees" of 1966, next to Norman Foster's shortlisted Twin Towers entry to the World Trade Center rebuilding competition. In the light of Oldenburg's proposed monumental homage to the first miniskirt 'n' boots era - two giant sections of leg on the skyline - you cannot help but see Foster's design as essentially a knock-kneed skyscraper. As it happened, "London Knees" sold well as a limited-edition mini-sculpture in a suitcase, rather than as a monument. Perhaps Foster could do likewise.

Finally, you get the architecture that was drawn for architecture's sake. When Philip Armstrong Tilden designed a colossal tower in 1918 to rise from the Selfridges department store in London, he most certainly did not expect to see it built. Nor did he. Tilden was employed as house architect by the bombastic Gordon Selfridge, and had to keep churning out design ideas in order to justify his salary. The tower, based upon the ancient mausoleum at Halicarnassus, might or might not have been intended as a tomb for the megalomaniac retailer. Take away the department store at its base, and you have a noble exercise in neoclassicism. With the store, it is ludicrously out of proportion. But today, we can see it as a forerunner for the explosion of architectural experimentation at Selfridges that took place under its director Vittorio Radice in the 1990s.