How do you build an underwater tunnerl?

New TED-Ed Originals                            How the world's longest underwater tunnel was built By Alex Gendler, directed by Bruno Simões Flanked by two powerful nations, the English Channel has long been one of the world's most important maritime passages. Yet for most of its history, crossing was a dangerous prospect. Engineers proposed numerous plans for spanning the gap, including a design for an underwater passage more than twice the length of any existing tunnel. Alex Gendler details the creation of the Channel Tunnel. View the animation »