cities that form Spain, while the plazas de soberanía are under a different status, akin to unincorporated territories. The African Mediterranean island of Alboran belongs to the transcontinental city of Almería and the transcontinental province of Almería. Asia and Africa : Although mainland Yemen is in the southern Arabian Peninsula and thus part of Asia, and its Hanish Islands, Zubair Group, and Perim in the Red Sea are associated with Asia, Yemen's national territory extends to the archipelago of Socotra, which lies east of the horn of Somalia and is much closer to Africa than to Asia. Asia and Europe : The territory of Greece includes a number of islands just off the coast of Asia Minor, such as Rhodes, Kos, Samos, Chios, Lesbos, Kastellorizo, Strongyli Megistis, and Ro. Asia and Oceania : The Commonwealth of Australia consists of its namesake continent and island possessions associated with Oceania, Asia, and Antarctica. Its Indian Ocean island possessions of Christmas Island and the Cocos (Keeling) Islands are sometimes geographically associated with Southeast Asia. The majority of residents on these islands have Asian ancestry; there is also a proportion of Australians and New Zealanders on the islands who have European ancestry. The islands have no proper indigenous population, as they were only discovered in the 17th century, by Europeans. Christmas Island and Cocos (Keeling) Islands are classified as being the westernmost areas of Oceania by the World Factbook, and are also considered part of Oceania by the United Nations. They are within the Australian Plate, and could potentially be geographically part of Oceania under definitions that include the nearby Malay Archipelago, or under definitions which are based on tectonic plates. : Japan's Izu islands and Bonin Islands (consisting of the Volcano Islands, and three remote islands; Nishinoshima, Minami-Tori-shima and Okinotorishima) are sometimes considered part of Oceania, owing to their oceanic nature. The Bonin Islands belong to the Oceanian biogeographic realm, and are believed to have once been inhabited by Indigenous peoples of Oceania around 2,000 years ago, with their official discovery coming much later in the 16th century, through Europeans. The most isolated island, Minami-Tori-shima (also known as Marcus Island) is 2,000 kilometers removed from Tokyo, lying closer to the northernmost islands of Micronesia. and : Indonesia (excluding Western New Guinea) and Timor-Leste are occasionally associated with Oceania, as they are the closest to Australia and Melanesia out of all countries in the