How Paris Built a Metro Tunnel Under a Busy Airport — But Still Can’t Open It

What happens after a giant tunnel boring machine finishes digging a metro tunnel? Beneath Paris and its suburbs, the Grand Paris Express is creating one of Europe’s most ambitious new transport networks. Giant tunnel boring machines work tens of meters underground while airports, railways, roads, homes, and everyday city life continue above them. But completing the tunnel is only the beginning. In this video, follow the engineering behind the Grand Paris Express—from massive tunnel boring machines and ground monitoring to underground stations, track installation, train testing, safety systems, and final commissioning. Discover why a finished tunnel can still be years away from carrying its first passenger, and why some of the most important work on a modern metro begins only after the digging ends. #TheBuildFrontier #MegaBuild #MegaEngineering