Obere Wasserschlosskammer - Guess what it is for and where it is....

It's a good video regardless..... Sort of gagging with anticipation.....

I think it's a surge tank in this system..... the halls are all similar in size and design... Could be somewhere else, but I don't have forever to look up all the underground hydroelectric systems around the world... https://www.youtube.com/watch?v=6Jx_bJgIFhI

There is something about getting sucked down that rectangular pipe, on the back stroke, and quite possibly getting smashed through screens or worsera ???? through a giant hydroelectric water turbine, that says, "No way would I liked to get sucked back down that hole with all the water etc... ".