AN air-to-air right side view of two F-101 Voodoo aircraft over Niagara Falls during exercise Sentry Castle '81. The aircraft are assigned to the 107th Fighter Interceptor Group, 136th Fighter Interceptor Squadron, New York Air National Guard

Niagara Falls is a group of three waterfalls at the southern end of Niagara Gorge, spanning the border between the US state of New York and the Canadian province of Ontario. The largest of the three is Horseshoe Falls, also known as Canadian Falls, which straddles the international border between Canada and the United States. The smaller American Falls and Bridal Veil Falls lie entirely within the United States. Bridal Veil Falls are separated from Horseshoe Falls by Goat Island and from American Falls by Luna Island, with both islands situated in New York as well. Located on the Niagara River, which drains Lake Erie into Lake Ontario, the combined falls have the highest flow rate of any waterfall in North America that has a vertical drop of more than 50 meters (160 ft). Niagara Falls is famed both for its beauty and as a valuable source of hydroelectric power. In 1881, the Niagara River's first hydroelectric generating station was built. The water fell 86 feet (26 m) and generated direct current electricity, which ran the machinery of local mills and lit up some of the village streets. In 1893, Westinghouse Electric designed a system to generate alternating current. In 1896, giant underground conduits leading to turbines generating upwards of 100,000 horsepower (75 MW), we installed.