Caroline Island (also known as Caroline Atoll or Millennium Island) is the easternmost of several uninhabited coral atolls comprising the southern Line Islands in the central Pacific Ocean nation of Kiribati. The atoll was first sighted by Europeans in 1606 and was claimed by the United Kingdom of Great Britain and Ireland in 1868. It has been part of the Republic of Kiribati since the island nation's independence in 1979. Caroline Island has remained relatively untouched and is one of the world's most pristine tropical islands, despite guano mining, copra (coconut meat) harvesting, and human habitation in the 19th and 20th centuries. It is home to one of the world's largest populations of the coconut crab and is an important breeding site for seabirds, most notably the sooty tern. The atoll is known as the first place on Earth to see sunrise each day during much of the year, and for its role in the millennium celebrations of 2000. A 1995 realignment of the International Date Line made Caroline Island the first point of land on Earth to reach 1 January 2000 on the calendar. History Prehistory The atolls (ring-shaped coral reefs) of the Pacific Ocean are the most marginal environment in the world for human habitation. They have generally not been occupied for more than 1,500 years, but started to be settled by humans once permanent islets formed around lagoons. In comparison with other atolls, Caroline Island has been relatively undisturbed. There are indications that early Polynesians reached the island before Europeans, as several marae (communal or sacred places) and graves have been discovered, but no evidence has been found of long-term settlement. Evidence of the largest of the marae, located on the west side of Nake Islet, was documented in 1883. Early sightings and accounts Ferdinand Magellan may have sighted Caroline Island on 4 February 1521. The first recorded sighting of Caroline Island by Europeans was on 21 February 1606, by the Portuguese explorer Pedro Fernández de Quirós, who named the island San Bernardo, and who wrote an account of his voyage. The island was next seen by Europeans on 16 December 1795, when the British naval officer William Robert Broughton of named it Carolina, after the daughter of Philip Stephens, the First Secretary of the Admiralty. The island was sighted in 1821 by the English whaler Supply, and was then named "Thornton Island" for the ship's captain.