Atoll remains of an ancient atoll as a hill in a limestone area is called a reef knoll. The second largest atoll by dry land area is Aldabra with 155 km². The largest atoll in terms of island numbers is Huvadhu Atoll in the south of the Maldives with 255 islands. In 1842, Charles Darwin explained the creation of coral atolls in the southern Pacific Ocean based upon observations made during a five-year voyage aboard from 1831 to 1836. Accepted as basically correct, his explanation involved considering that several tropical island types—from high volcanic island, through barrier reef island, to atoll—represented
Dhaalu Atoll Dhaalu Atoll Dhaalu' Atoll (also known as Southern Nilandhe Atoll or Nilandhe Atholhu Dhekunuburi) is one of the atolls of the Maldives. It corresponds to the natural atoll of the same name. It stretches 23km (14 mi) from east to west, and 38km (24 mi) north to south. Out of a total of 56 islands, seven of the islands are inhabited, with a total population of around 6694. The capital island is Kudahuvadhoo, located at the atoll's southern tip. Hulhudheli and Rinbudhoo (Rimbudu) islands, located to the west of this atoll, are islands traditionally renowned for the skill of their