A series of familiar images unfolds on the screen: a wall of glass towers, a Brazilian favela, the Shibuya pedestrian crossing in Tokyo. Visual shorthand for a crowded planet, they are accompanied by an equally familiar sequence of statistics: half of humanity – or 3.5 billion people – now live in cities, and urbanisation is so rampant that by 2050 this figure is projected to be 75%. So begins Urbanized, a new film about the challenge that cities pose in the 21st century, which had its London debut this weekend, playing to a packed house at the London School of Economics. It is directed by Gary Hustwit, who made the cult hit Helvetica in 2007 (an unlikely film about a Swiss typeface) before taking on the much broader topic of industrial design in 2009’s Objectified. With Urbanized, he zooms out even further to complete his trilogy, a cinematic story about design moving from the micro to the macro.