Henderson Island (Pitcairn Islands) in the context of "Gastropods"

A raised coral atoll or uplifted coral atoll is an atoll that has been lifted high enough above sea level by tectonic forces, protecting it from scouring by storms and enabling soils and diverse – often endemic – species of flora and fauna to develop. With the exception of Aldabra in the Indian Ocean and Henderson Island in the Pacific Ocean, most tropical raised atolls have been dramatically altered by human activities such as species introduction, phosphate mining, and even bomb testing.

The Pitcairn Islands (/ˈpɪtkɛərn/ PIT-kairn; Pitkern: Pitkern Ailen), officially Pitcairn, Henderson, Ducie and Oeno Islands, are a group of four volcanic islands in the southern Pacific Ocean that form the sole British Overseas Territory in the Pacific Ocean. The four islands—Pitcairn, Henderson, Ducie and Oeno—are scattered across several hundred kilometres (miles) of ocean and have a combined land area of about 47 square kilometres (18 square miles). Henderson Island accounts for 86% of the land area, but only Pitcairn Island is inhabited. The inhabited islands nearest to the Pitcairn Islands are Mangareva (of French Polynesia), 688 km (428 miles) to the west, as well as Easter Island, 1,929 km (1199 miles) to the east.

The Pitcairn Islanders are descended primarily from nine British HMS Bounty mutineers and twelve Tahitian women. In 2023, the territory had a permanent population of 35, making it the smallest territory in the world by number of permanent residents. Owing to the island's extreme isolation and small population, incidents of widespread sexual abuse went undetected until 1999, culminating in a high-profile sexual assault trial in 2004.

Ducie Island (/ˈduːsi/; Pitkern: Ducie Ailen) is an uninhabited atoll in the Pitcairn Islands group, which also includes Pitcairn, Henderson and Oeno islands. Ducie lies east of Pitcairn Island, and east of Henderson Island, and has a total area of 1.5 square miles (3.9 km), which includes the lagoon. It is 1.5 miles (2.4 km) long, measured northeast to southwest, and about 1 mile (1.6 km) wide. The island is composed of four islets: Acadia, Pandora, Westward and Edwards.

Despite its sparse vegetation, the atoll is known as the breeding ground of a number of bird species. More than 90% of the world population of Murphy's petrel nests on Ducie, while pairs of red-tailed tropicbirds and fairy terns make around 1% of the world population for each species.

Oeno Island (/oʊˈiːnoʊ/ oh-EE-noh) or Holiday Island is an uninhabited coral atoll in the South Pacific Ocean, part of the Pitcairn Islands overseas territory. It is part of the Pitcairn Island Group, together with Pitcairn, Henderson and Ducie islands.

Essex was an American whaling ship from Nantucket, Massachusetts, which was launched in 1799. On November 20, 1820, while at sea in the southern Pacific Ocean under the command of Captain George Pollard Jr., the ship was attacked and sunk by a sperm whale. About 2,000 nautical miles (3,700 km) from the coast of South America, the 20-man crew was forced to make for land in three whaleboats with what food and water they could salvage from the wreck.

After a month at sea, the crew landed on the uninhabited Henderson Island. Three men elected to stay on the island, from which they were rescued in April 1821, while the remaining seventeen set off again for the coast of South America. The men suffered severe dehydration, starvation and exposure on the open ocean, and the survivors eventually resorted to cannibalism. By the time they were rescued in February 1821, three months after the sinking of Essex, only five of the seventeen were alive.