The Stopping of Niagara Falls in 1969

(via Amusing Planet)  Due to several years of rocks falling in, between the year 1931 and 1954, the American Falls part of Niagara Falls faced erosion, which if not prevented would have resulted in the permanent extinction of the American Falls. With resulting public outcry and protests to save the American Falls, the United States Army Corps of Engineers (USACE) – Buffalo district was encumbered with the immense responsibility of dewatering the American Falls for repairs.