Islas Revillagigedo

The Revillagigedo Islands are a group of four volcanic islands in the open Pacific: Socorro, San Benedicto, Roca Partida and Clarión. They lie about 460 km south and southwest of Cabo San Lucas and between about 700 and 1,100 km west of Manzanillo, spread over some 420 km from east to west, with a total land area of about 158 km². Socorro is by far the largest, at 132 km², and rises to 1,130 m at Cerro Evermann; San Benedicto (6 km²) is crowned by the Bárcena volcano, Clarión (20 km²) lies more than 200 km to the west, and Roca Partida is a bare rock 34 m high. The islands are federal territory, but a decree signed by Benito Juárez in 1861 gave them to the state of Colima, originally for a penal colony that was never built, and they are counted as part of the municipality of Manzanillo.

Spanish sailors from Hernando de Grijalva's expedition sighted Socorro and San Benedicto in December 1533, and Ruy López de Villalobos passed again in 1542 and first reported Roca Partida. The group takes its name from the Count of Revillagigedo, viceroy of New Spain in the 1790s. The islands are still volcanically active: on 1 August 1952 Bárcena erupted and almost wiped out life on San Benedicto, and Socorro last erupted in 1993. The only residents are Mexican Navy personnel, at a base on Socorro set up in 1957 and a smaller post on Clarión. Isolation has produced a distinctive wildlife, which has earned the islands the nickname of Mexico's little Hawaii: 14 of the 16 resident land-bird taxa are endemic, the Socorro dove survives only in captivity, and the Socorro mockingbird numbers fewer than 400 birds.

The islands became a biosphere reserve in 1994, were inscribed as a UNESCO World Heritage Site in July 2016, and in November 2017 Mexico declared the Revillagigedo National Park, a marine protected area of about 150,000 km² where all fishing, mining and tourism development are banned. For visitors, the islands are one of the world's great big-animal dive sites: giant manta rays at the cleaning stations of San Benedicto, sharks around Roca Partida, and dolphins and other cetaceans. There are no tourist facilities and no reliable fresh water on the islands, so trips are made on liveaboard boats that cross from Cabo San Lucas in about 24 to 30 hours and stay at sea for a week or more, with dives rotating between Socorro, San Benedicto and Roca Partida.