Waterfalls are found in two kinds of places: where there are soft and hard layers of rock lying as flat sheets, and where glaciers have carved deep trenches during the Ice Age.

Usually the river flows quite slowly before it reaches the waterfall. The top edge of a waterfall is called the lip. The part where the water drops is a cliff, called the fall. At the bottom, the water, and stones it is carrying, wear out a deep pool. This is called a plunge pool.

There are many spectacular waterfalls. You can see them in the book 'Waterfall'. Niagara Falls is one of these. The water from the Niagara River comes from the Great Lakes. As it approaches the falls, it flows in a wide channel divided by islands. One branch produces the Horseshoe Falls (also called the Canadian Falls), which you can see here.

Look for the small tourist boat below the falls and in the rainbow. You can travel on this boat – called Maid of the Mist – and get a spectacular, if spray-drenched, view of the falls, while listening to its deafening roar.

The Horseshoe Falls drop about 53m and the American Falls about 30m. The Horseshoe Falls are 790m and the American Falls 320m wide.