Every 12 years, a megacity springs up in India for the Kumbh Mela religious festival -- what's built in ten weeks is completely disassembled in one. What can we learn from this fully functioning, temporary settlement? In a visionary talk, urban designer Rahul Mehrotra explores the benefits of building impermanent cities that can travel, adapt or even disappear, leaving the lightest possible footprint on the planet.

Transcript in English