Scorpion Reef (Spanish: Arrecife Alacranes) is a reef, located in the Campeche Bank (22°27′00″N 89°42′00″W / 22.450°N 89.700°WCoordinates: 22°27′00″N 89°42′00″W / 22.450°N 89.700°W). It is the largest reef in the Southern Gulf of Mexico. The reef contains five vegetated islands; Isla Pérez, Isla Desertora, Isla Pájaros, Isla Chica and Isla Desterrada. Isla Pérez is the only inhabited island, and also is the site of a lighthouse. The reef is a national park in Mexico, and was decreed a "Reserve of the Biosphere" by the United Nations in 1994.