Niagara Falls travel guide from Wikivoyage Panorama Niagara Falls Panorama found at Queen's Park, Toronto. Historic Niagara Digital Collections U.S. Army Corps of Engineers The U.S. Army Corps of Engineers completely blocked the flow of water over the American Falls in 1969. The History of Niagara Falls "Niagara Power Goes Under Ground" Popular Mechanics, April 1952, pp. 115–117.