Equatorial Guinea, officially the Republic of Equatorial Guinea, is a country located on the west coast of Central Africa, with an area of 28,000 square kilometres (11,000 sq mi). Formerly the colony of Spanish Guinea, its post-independence name evokes its location near both the Equator and the Gulf of Guinea. Equatorial Guinea is the only sovereign African state in which Spanish is an official language. As of 2015, the country had a population of 1,225,377. Equatorial Guinea consists of two parts, an insular and a mainland region. The insular region consists of the islands of Bioko (formerly Fernando Pó) in the Gulf of Guinea and Annobón, a small volcanic island which is the only part of the country south of the equator. Bioko Island is the northernmost part of Equatorial Guinea and is the site of the country's capital, Malabo. The mainland region, Río Muni, is bordered by Cameroon on the north and Gabon on the south and east. It is the location of Bata, Equatorial Guinea's largest city, and Ciudad de la Paz, the country's planned future capital. Equatorial Guinea has become one of sub-Saharan Africa's largest oil producers however, the wealth is distributed extremely unevenly, with few people benefiting from the oil riches. Equatorial Guinea's government is authoritarian and has one of the worst human rights records in the world.