Contrary to what super villains or mole men would have you believe, it takes more than a giant machine to tunnel through millions of tons of dirt and water — but having one doesn’t hurt.
Photo: Construction of the Channel Tunnel completed in 1994 and stretches for nearly 50kms.
Still, for most of our tunnel-digging history, we’ve managed to get by on ingenuity. Humans have tunneled since the first cave dwellers decided to excavate a spare bedroom, and the essentials of dig, support and advance were well-refined by the time the ancient Greeks used tunnels to irrigate and drain their farmland.
Underwater tunnels, too, are surprisingly old. Sometime between 2180 and 2160 BCE, the Babylonians built one of the first known examples by diverting the Euphrates River. The 3,000-foot (900-meter) brick-lined and arch-supported tunnel, which measured 12 feet high by 15 feet wide (4 meters by 5 meters), provided a pedestrian and chariot passage between the royal palace and the temple [sources: Lane; Browne].
READ MORE : How do you build an underwater tunnel?