Switzerland Built a Tunnel So Impossible Even Americans Can't Believe It's Real

Deep inside a Swiss mountain, a crew sent a 290 ton machine climbing straight up a hole it was digging. One slip and it would slide 800 meters back down and take everyone with it. Then the mountain hit back three times. A flood the experts called unstoppable. A roof that started vanishing over their heads. A hole where solid rock should have been. This is how they beat all three and turned a mountain into the world's biggest kind of battery. I spent forty years building this kind of thing, and it still stopped me cold. #engineering #tunnel #megaprojects #switzerland #hydropower #pumpedstorage #construction #tunnelboringmachine #TBM #civilengineering #infrastructure #howitsmade #documentary #engineeringmarvels #alps