The world is urbanizing. According to a UN report, 54 per cent of the world's population lived in an urban area in 2014 – by 2050, that will have risen to roughly two thirds. This begs the question: how can a high quality of life be ensured in these metropolises? Are we threatened with a dystopian future of cities choked by traffic or waste, with blackouts, a lack of drinking water, and millions of people without work? Or do innovative technologies have the potential to create a city worth living in?