Niagara Falls is located on the Niagara River in eastern North America, on the border between the United States and Canada. The name refers to three separate waterfalls: the American Falls, the Bridal Veil Falls, and the Horseshoe Falls (known in Canada as the Canadian Falls). While not exceptionally high, Niagara Falls is very wide, and a large volume of water passes over it. The scenic view attracts millions of visitors, especially in the summertime. The name "Niagara" is said by some to originate from an Iroquois word which can be interpreted as "Thunder of Waters". Niagara Falls was brought to the world's attention in the 17th century by the explorer Father Louis Hennepin, who also discovered the Falls of Saint Anthony.
The Falls drop about 170 feet although the American Falls have a clear drop of only 70 feet before reaching a jumble of rocks at its base. The American Falls are 1060 feet wide and the Canadian Falls are about 2600 feet wide. There is nighttime illumination of both falls from Canada.
The Niagara River drains four of the North American Great Lakes into the lowest Great Lake, Lake Ontario. The lakes and the Niagara river are effects of the last continental ice sheet, an enormous glacier that crept across the area from eastern Canada. The ice, which could be envisioned as a mile-high bulldozer, ground up rocks and soil, moved them around, deepened some river channels to make lakes, and dammed others with debris, forcing these rivers to make new channels. After the ice melted back, drainage from the upper Great Lakes became the present Niagara River and cut a brand new valley. When the river encountered a hard layer or rock, known as the Lockport dolomite, a waterfall was formed. The original waterfall was next to present day Lewiston, New York, but the current waterfalls actually have retreated several miles southward by erosion of the crest of the falls. Ultimately the falls will retreat back far enough to drain Lake Erie, which is not as deep as the height of the falls. Engineers are working to reduce the rate of erosion to retard this event as long as possible.
A portion (50% to 75%) of the river's flow is diverted from the visible waterfall to hydroelectric turbines that supply power to nearby areas of the United States and Canada.