*When a stream or river flows over a cliff and plunges downward, it forms waterfalls. Cataract is a term used for giant waterfall. With their great power and beauty, the cataracts are among the most impressive of the natural wonders on earth.

• Niagara falls are one of the most spectacular natural wonders in North America. The falls are on the Niagara River which flows between the United States and Canada.

About 12, 000, 000 cubic feet of water pours over the cliffs of the falls of Niagara every minute. As the water plunges from the brink of the falls, it fills the air with a silvery mist. This under the sunlight displays many rainbows.

The plunging water has worn away the lower ricks, forming caves behind the sheets of water falls. Sightseers may enter the cave of the winds and get unusual view.

• The spectacular Lguassu falls are locked on a stretch of the Lguassu River that forms the boundary between Brazil and Argentina.

The horseshoe –shaped Lguassu falls are nearly three times wider than Niagara Falls. The falls divided into about 275 separate waterfalls with height between 200 and 269 feet.

The splashing water, along with the spray that forms, creates a series of rainbows. Visitors can get soaking wet just by standing in the mist and spray near the waterfalls.

• Angle falls are on the Churun River in southeastern Venezuela. Angle falls are the highest waterfall in the world. They are 3, 212 feet high i.e. about 20 times higher than Niagara Falls.

Because of the dense jungle surrounding it, the waterfall can best be viewed from the air, although Angle falls are difficult to visit, tourists may go there with guides.

• Jog falls are on Sharavati River in Karnataka, India. The Jog waterfalls plunge 830 feet into a chasm, splitting into four cascades known as the Raja, Roarer, Rocket and Ranee.

A scenic attraction, the falls can be observed from bungalows on either bank of the river.