More than 300 years ago, Father Louis Hennepin was the first European to be led to Niagara Falls by native Americans. The chaplain of Robert Cavalier sieur de La Salle's expedition has a falls that since has eroded the caprock considerably, with more than a million gallons of water a minute passing over it. The Niagara River is only 33 miles long, with Lake Erie as its sole tributary. The river, including the 176-foot-high falls, carries the water of four of the Great Lakes through the Niagara Gorge and into Lake Ontario. The pool at the base of the falls is as deep as the falls are high.