PBS
Wgbh: Building Big: Tunnels
A collection of resources about tunnels that includes basic facts about tunnels, challenges faced by tunnel diggers, famous tunnels from around the world, and a lab that helps you understand the kinds of forces that keep tunnels from...
TED Talks
Ted: Ted Ed: How the World's First Metro System Was Built
Christian Wolmar explains how the London Underground was built at a time when no one had built a railway under a city before.