About Hoover Dam, Las Vegas

Welll... that's where all those lights come from. Yep. The dam is a massive construction looking as a curved wall, 660 feet thick at the bottom and it towers 726 feet ( that's about the height of a 60 story building). It acts like a plug between the canyon walls to hold about 9,2 trillion gallons of water in Lake Mead which resulted after its construction. Here's how it's actually working:
4 concrete intake towers on the lake side drop the water 600 feet down to drive the turbines and create power,; after that the water is poured into the river and continues flowing to the south.