(1) The main island, the Tarawa atoll , is only a few metres above sea level and houses around 40,000 people.

(2) Reefs are generally divided into three categories; the barrier reef, the atoll , and the fringing reef.

(3) All the islands were formed by volcanic activity and can be divided into atolls and high islands.

(4) Hidden beneath the salty Pacific, the coral atolls along the northwestern Hawaiian chain put an abrupt end to many a daring seafarer's adventure.

(5) Diving is generally within the atoll lagoons for the inexperienced, and outside the atolls on reef walls for the advanced.

(6) The Maldives include nearly 1,200 islands in 15 major atolls spanning approximately 470 miles to just south of the equator.

(7) The tsunami swamped up to 40 percent of the Maldives, an Indian Ocean string of 1,192 coral atolls 480 km southwest of the southern tip of India.

(8) The northern islands are coral atolls that have formed over ancient sunken volcanoes and are characterized by outer reefs surrounding a lagoon.

(9) Acknowledged as the world's greatest dive destination, however, are the Maldive Islands in the Indian Ocean with enough coral atolls and underwater life to satisfy the most demanding diver.

(10) There are at least 1000 islands in the chain of 19 atolls which make up the Maldives.

(11) The islands, atolls and reefs are believed to sit atop vast mineral and oil deposits.

(12) The Marshall Islands are a group of low-lying coral atolls and islands in the central Pacific Ocean.

(13) On outer islands and atolls , however, most matters are settled internally, with little reliance on the state judicial apparatus.

(14) Chants and oral traditions suggest native Hawaiians also visited other islands and atolls in the chain.

(15) Banaba is a raised limestone island, but the other islands are all coral atolls , and most have lagoons.

(16) The Philippines is an archipelago of 7,100 islands, islets, and atolls located southeast of the Asian mainland.

(17) The islands of the Maldives are grouped in ring-shaped coral atolls , each enclosing a relatively shallow lagoon with a flat sandy bottom.

(18) She had chosen a peaceful, romantic holiday in the southern atolls on a small island with only 50 huts.

(19) In their voyage through the remote islands and atolls they seldom took the boy ashore, fearing infection.

(20) Tuvelu is one of the smallest countries on earth, a chain of nine coral atolls whose highest point is just a few meters above sea level.