Himalayas
The Himalayas consist of some highest peaks of mountains in the world like Everest, Kanchanganga and Lhotse. Nepal is situated in a valley between the Mahabharat and lesser Himalaya mountain ranges. I
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Coasts
How are islands formed?
Climate
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Continents
The ocean currents of Atlantic
Conservation info: Protection of natural resources
A simplified section across the Great Barrier Reef of Australia shows how a faulted area has submerged and formed a suitable platform for coral growth. The barrier reef is in fact a complex series of smaller reefs.
Coral
Coral is a formation of limestone built up in the sea by millions of tiny animals called coral polyps. Each polyp is a jelly-like animal that builds a cup of limestone around itself. As in anemones, to which corals are related, the mouth is surrounded by tentacles carrying stinging cells and used to paralyze prey.
Most corals live in colonies. The limestone cups, or skeletons, of the many individual polyps in a colony form a branching formation of limestone in the sea. As the polyps reproduce, so the formations get larger.
Some formations can be delicate and lace-like. But others build into great coral reefs and atolls. Reef-building corals live only in the tropics, as they cannot survive in water with a temperature lower than 18° C (65° F). Other corals can be found in cooler waters. Many coral formations have beautiful colors. This is caused by the polyps themselves, and if the formation is removed from the water the polyps die and the color fades.
Coral reefs form at depths of not more than 150 feet and grow until they break the surface. 
There are three kinds of coral reefs. Fringing reefs are found along a shore, extending only half a mile out to sea. Barrier reefs are situated offshore, separated from the land by a deep channel (as in the Great Barrier Reef along the east coast of Australia) or a lagoon, which may be many miles wide. Barrier reefs are mostly found around small islands in the ocean. Coral atolls are great ring-shaped reefs. Coral islands form when sediment and debris build up on a barrier reef or atoll.
