As a world-famous destination visited by more than 20 million tourists each year, it's no wonder people are curious about these amazing waterfalls and want to know more about them.

The Falls were created when glaciers began to recede at the end of the Wisconsin glacier period, with the water coming from the newly formed Great Lakes. A path was formed through the Niagara Escarpment by the slowly retreating ice. The waterfalls are estimated to be approximately 12,000 years old, and the name comes from the Iroquois word "onguiaahra", which is their word for "the straight". Originally, the falls was 7 miles farther downstream from where it is now. Erosion slowly causes the falls to move every year.

Another historical fact about Niagara Falls is that it was first discovered by a European in 1678, by a Franciscan monk and explorer named Louis Hennepin. It didn't become a major tourist destination until the 1800s though. The river was dammed to create power for the first time in 1881.

Located between New York state in America and the province of Ontario in Canada, the Falls are right on the international border between the countries. In terms of the next largest cities, Buffalo NY is 23 miles away and Toronto, ON is 79 miles away. There are actually 2 cities called Niagara Falls, one in each country.

The Falls themselves are 176 feet high, which is certainly not that impressive compared to many higher falls in the world. But the width is 1,060 feet which means Niagara Falls is one of the most powerful waterfalls on the continent in terms of how much water rushes over. Because of their shear size, the water never stops even in the frozen dead of winter. Even so, there can be huge formations of ice right across the river if it gets cold enough.

There are actually 3 sets of waterfalls at Niagara. The American falls are between Luna Island and Prospect Place, and the Bridal Falls are between Luna Island and Goat Island. The larger Canadian Falls lie between Goat Island and Tablerock. Because of the location of Goat Island, the water flow over the American Falls is considerably lower than the main Horseshoe Falls.

The first large-scale hydroelectric power generating dam in the world was build at the American Falls in 1895. Since more than 5 billion gallons of water pour over the falls, there is a great deal of power to be created. Half of the water is diverted to generation electricity for both Canada and the United States. It's the largest hydroelectric power source in the world.

Believe it or not, even these huge waterfalls have gone dry. Twice, in fact. The first time was in 1848 and it was because of an ice jam farther up the river, and also again in 1969 as part of a project to remove some of the rocks at the bottom of the falls. That particular project was never completed.

Niagara Falls aren't only popular with honeymooners. Several major movies have been filmed here. Superman and Pirates of the Caribbean both had scenes filmed at the falls, as did the Marilyn Monroe movie, Niagara.

At nights, the Falls are lit up for a very beautiful view but the reason is actually to help cover up the fact that water has been diverted through the hydro plant. By lowering the water level each night, the natural erosion of the Falls has been greatly reduced and now the falls only shifts position by a few inches per year instead of several feet. That's one of the little known facts about Niagara Falls.