With new technology, humans are building taller and taller residential – and luxury – skyscrapers. But “the payoff for peace and endless views can be five-minute waits for the lift at rush hour – and even sunburn. ‘You could get tanned in winter if you sat right by the window: there’s a bit of a greenhouse effect,’ the owner of a 64th-floor apartment above Chicago tells me. Vertigo can be another danger.”