Both Frankfurt and the BBC were significant projects that never reached completion; but whereas the indoor athletics stadium, winner of a restricted competition in 1981, substantially develops and extends the concept of the Sainsbury Centre, the new premises of the media company broke entirely new ground in the work of Foster. The stadium was essentially an extruded building, with a half sunken flattened vault and glazed end facades sheltered by canopies, which keeps its low tense profile subordinated to the surrounding trees. The BBC project, on the other hand, occupied a critical urban site facing the round portico and conical spire of Nash’s All Souls Church, and was drawn for the hugely complex mythical Broadcasting Corporation, adding the labyrinthine intricacy of the programme to the puzzling complexity of the place. After many models exploring alternatives, the final version used a diagonal geometry – based in the 3-4-5 triangle – to connect, with a huge public atrium, All Souls with Cavendish Square in the opposite corner of the site, stepping the building to mediate between the scale of the church and that of the residential square. In the midst of the historicist revival of postmodernism, Foster showed how to deal with the past using only modern tools...[+]