Tunnelling under London and what came first – the chicken or the egg?

Crossrail is one of Europe's biggest engineering projects ever, involving 26 miles of tunnels under London. Chris Binns is a chief engineer from the project and tells Dan about immense job of digging right underneath the capital and the challenges they faced along the way!

Plus, Sir Sidney McSprocket's jumping back in time to find out about a clever invention to keep your tea warm, we discover a dangerous job - hurricane hunting - and our science expert Tom settles an age-old discussion: what came first, the chicken or the egg?