Located in the South Atlantic Ocean on the Mid-Atlantic Ridge, more than 2,000 kilometres (1,200 mi) from the nearest major landmass, Saint Helena is one of the most remote places in the world. The nearest port on the continent is Namibe in southern Angola, and the nearest international airport the Quatro de Fevereiro Airport of Angola's capital Luanda; connections to Cape Town in South Africa are used for most shipping needs, such as the mail boat that serves the island, the RMS St Helena. The island is associated with two other isolated islands in the southern Atlantic, also British territories: Ascension Island about 1,300 kilometres (810 mi) due northwest in more equatorial waters and Tristan da Cunha, which is well outside the tropics 2,430 kilometres (1,510 mi) to the south. The island is situated in the Western Hemisphere and has the same longitude as Cornwall in the United Kingdom. Despite its remote location, it is classified as being in West Africa by the United Nations.