Im surprised at how this isn't flooded. Str8 up amazing.

This reminds me a lot about the old (1910-1915) powerplants in northern Sweden. 60-90 meters down into the ground, these tunnels are incredibly beautiful. Perhaps a future place for you turists. :)

The tunnels can't flood since they run downhill. The only flooding is at the very end where rocks have partially clogged the opening. wish I could go down there for a personal look.