Italy
The Peshtera Hydro Power Plant (before 1992: Kimon Georgiev Hydro Power Plant) is an active underground hydroelectric plant in Peshtera, Bulgaria. It is part of the Batak Hydropower Cascade. It has 5 individual Pelton turbines which can deliver up to 136 MW of power.
Listen to the audio guide for Peshtera Hydroelectric Power Station Free on WIP — starts by itself when you arrive, even with the screen off