Bir Tawil (meaning "tall water well") is a 2,060 km² area along the border between Egypt and Sudan, which is claimed by neither country, making it the only current terra nullius outside of Antarctica.
In 1899, when the United Kingdom held hegemony in the area, the Anglo-Egyptian Condominium Agreement for Sudan set the border between the territories at the 22nd parallel. However, in 1902 the UK drew a separate "administrative boundary", intended to reflect the actual use of the land by the tribes in the region. Bir Tawil was grazing land used by the Ababda tribe based near Aswan, and thus was placed under Egyptian administration from Cairo. Similarly, the Hala'ib Triangle to the northeast was placed under the British governor of Sudan, because its inhabitants were culturally closer to Khartoum.
Egypt claims the original border from 1899, the 22nd parallel, which would place the Hala'ib Triangle within Egypt and the Bir Tawil area within Sudan. Sudan however claims the administrative border of 1902, which would put Hala'ib within Sudan, and Bir Tawil within Egypt. As a result, both states claim the Hala'ib Triangle and neither claims the much less valuable Bir Tawil area, which is only a tenth the size, and has no permanent settlements or access to the sea. There is no basis in international law for either Sudan or Egypt to claim both territories, and both nations are unwilling to cede Hala'ib. With no third state claiming the neglected area, Bir Tawil is one of the few land areas of the world which is not claimed by any recognised state. Egypt arguably still administers the territory, but it is not marked as Egyptian on government maps.