Produced as a diploma project in 1928, it justified itself by pointing out – as generations of environmentalists would later insist – the need to minimise human impact on the planet. Except rather than treading lightly on it, we wouldn't be treading on it at all, but living in flying mobile homes, which could dock at collective housing, hotels, factories and leisure centres, able to descend to the earth to enjoy it unspoilt. — guardian.co.uk

Richard Rogers's 1986 headquarters for the insurers Lloyd's of London has just been listed Grade I. This makes it, along with the Royal Festival Hall, one of the few 20th-century structures to be placed at the same level as, say, St Paul's. But, like the gothic cathedrals it so closely resembles, Lloyd's was not meant to be an entirely finished product. Look up to the top of its facade, and you'll find cranes are still there... — guardian.co.uk

This was the city of the 20th Century, but surely nobody, neither utopians or dystopians, imagined that it would look like this. It was nobody's dream and at least in theory, nobody's nightmare. How did we get here? — BBC