 3,160 tons of water flows over Niagara Falls every second. This accounts for 75,750 gallons of water per second over the American and Bridal Veil Falls and 681,750 gallons per second over the Horseshoe Falls  The water falls at 32 feet per second over the falls, hitting the base of the falls with 280 tons of force at the American and Bridal Veil Falls and 2,509 tons of force at the Horseshoe Falls.  Four of the five Great Lakes drain into the Niagara River, (Superior, Michigan, Huron and Erie) before emptying into Lake Ontario. These five Great Lakes make up almost one-fifth of the world's fresh water supply.  The first European to see and describe Niagara Falls in depth was Father Louis Hennepin, a French priest who accompanied LaSalle on his expedition to the Niagara region in 1678.  The largest vertical drop is over 165 feet (50 meters)  The first tightrope walker to cross the Niagara Falls did so in 1859  American and Bridal Veil Falls: Length – 1060 Feet, Height 176 Feet  Horseshoe Falls: Length 2060 Feet, Height 167 Feet  The falls were created by glacial activity 10,000 years ago.  The falls are a source of hydropower, producing great amounts of electricity.  Water is diverted from the falls to power plants.  The Falls are capable of producing over 4 million kilowatts of power.  The flow of water was stopped completely over both falls on March 29th 1848 due to an ice jam in the upper river for several hours.  The flow was stopped to the point that people walked out and collected artifacts from the river bed.  The flow over the American Falls was stopped completely for several months in 1969 due to an earthen dam built by the United States. The idea was to determine the feasibility of removing the large amount of loose rock from the base of the falls to enhance its appearance. In the end the final decision was that the expense would be too great.