Over a million gallons of water per second flows over the 180-foot-high cliff at Niagara Falls. One of the natural wonders of the world, the cliff at Niagara is a little over a half a mile wide.
The rapids above the falls can reach maximum speeds of up to 25 miles per hour, with the fastest speeds being in the falls themselves at around 68 miles per hour. Because of this, Niagara may be one of the fastest moving waterfalls in the world, and due to the erosion from the water, the falls have moved back approximately seven miles over the course of 12,500 years.
