NIAGARA WATERFALLS

Niagara is a big waterfall on the Niagara River in the international boundary line between United States state of New York with the Canadian province of Ontario. Niagara Falls is about 17 miles or about 27 km north northwest of Buffalo, New York and 75 miles (120 km) southeast of Toronto, Ontario, between the twin cities of Niagara Falls, Ontario, and Niagara Falls, New York.
Niagara is a group of three waterfalls. The third waterfall is a waterfall Horseshoe (sometimes referred to as the waterfall Canada), American waterfall, and a smaller, Bridal Veil waterfalls are separated by an island called Luna Island. Although not very high, Niagara Falls is a waterfall that is very wide and most popular in the world. More than 6 million cubic feet (168,000 m3) of water per minute dropped and this is the most powerful waterfall in North America.
Niagara is also famous for the beautiful rainbow that ran in the middle of the swift waterfall. Natural beauty found around Niagara makes millions of people from all over the world visit it every day. In addition to beauty, Niagara also known as a valuable source of hydroelectric power. Managing the balance between recreational, commercial and industrial have used a challenge for the servants of the fallen since the 1800s.
The peak number of visitors occur in the summer, when the Niagara Falls attraction both day and night. From the Canadian side, floodlights illuminate both sides of the waterfall for a few hours after dark (until midnight). Number of visitors in 2008 expected to reach 20 million and in 2009, the annual rate is expected to top 28 million tourists a year. The oldest and most famous tourist attractions in Niagara Falls is a yacht Maid of the Mist, named for an ancient Indian myth Ongiara, which has been carrying passengers into the whirlpools beneath the falls since 1846. Cruise ships operate from boat docks on both sides of the waterfall
The formation of the Niagara gorge (downriver) and the maintenance of the falls as a cataract depend upon peculiar geologic conditions. The rock strata from the Silurian Period (about 445 to 415 million years ago) in the Niagara gorge are nearly horizontal, dipping southward only about 20 feet per mile (almost 4 metres per km). An upper layer of hard dolomite is underlain by softer layers of shale. Water exerts hydrostatic pressure and only slowly dissolves the dolomite after infiltrating its joints. Dolomite blocks fall away as water from above infiltrates and rapidly erodes the shale at the falls itself. The disposition of the rock strata provides the conditions for keeping the water constantly falling vertically from an overhanging ledge during a long period of recession (movement upstream) of the cataract. As blocks of dolomite are undercut they fall off and are rapidly destroyed by the falling water, further facilitating the retreat of the falls and the maintenance of a vertical cataract.