USA 🇺🇸 In Lake Berryessa in California there is a large hole right in the middle of the lake, which is neither a natural phenomenon nor an illusion. This unusual structure, shaped like a funnel, is part of the hydraulic engineering system that ensures the safety of the dam. When the water level in Lake Berryessa rises greatly, the funnel opening allows excess water to escape without causing damage to the dam. | World Beauty