“A century ago, only about 10 per cent of the world’s population lived in cities. By 2050 that figure is expected to rise to at least 75 per cent. The great thing about cities is not how awful they are, but how wonderfully well they work, considering that putting more than 20 million humans in close proximity to engage in serial acts of competitive individualism could not be considered a reasonable idea. If you put rats into claustrophobic circumstances, they become cannibalistic in no time at all. But humans find ingenious solutions: Maglev trains, underground car parks, Korean supermarkets, pizza delivery, cycle lanes, very tall buildings.”