The Glory Hole Lake Berryessa

Glory holes are used for dams to drain excess water during dry seasons. This is the largest one of them all in the world, it is located in Lake Berryessa. It is used very rarely, but it is quite the sight to see it being put to use.This open bell-mouth spillway (basically what lets them release flows of dam water into Putah Creek) is one of the coolest things you'll ever stare into (from a very, VERY safe distance) in your life. Creepy bonus: The lake was the site of one of the Zodiac murders! Located in Napa County, California, USA this glory hole was constructed between 1953 and 1957. The hole diameter is 72ft (22m) wide