Although not very high, Niagara Falls is very wide. With more than 6 million cubic feet (168,000 m³) of water falling over the crestline every minute in high flow, and almost 4 million cubic feet (110,000 m³) on average, it is the most powerful waterfall in North America.
Niagara Falls formed after the receding of the glaciers of the most recent Ice Age, as water from the newly formed Great Lakes carved a path through the Niagara Escarpment en route to the Atlantic Ocean.
From the Canadian side, floodlights illuminate both sides of the Falls for several hours after dark (until midnight). The number of visitors in 2007 is expected to total 20 million and by 2009, the annual rate is expected to top 28 million tourists a year.
Also see: Iguazu Falls