Bouvetoya (54° 42' S, 03° 37' E) is the most isolated island on earth. The nearest substantial land mass is more than 1600km (990mi) away. Glaciers cover 93% of the 54 sq km (21 sq mi) island and prevent landings on the south and east coasts, while steep cliffs as high as 490m (1607ft) block access to the north, west and southwest. Sometime between 1955 and 1958, a low-lying shelf of lava appeared on Bouvetoya's west coast, providing the only bird nesting site of any size on the island. The island is rarely visited, but two events in its history are rather mysterious: first, a sunken lifeboat and assorted supplies were discovered on the island in 1964, but their origin could not be determined. Then, in September 1979, a thermonuclear bomb blast was detected to the west of Bouvetoya, though no country ever admitted to setting off a nuclear device there.

There are reports of a curious assortment of non-existent islands, all recorded in the Southern Ocean or the extreme southern limits of the adjoining oceans. Most have appeared on official charts, several have been seen more than once, and three may have once existed but been submerged following volcanic explosions.Besides volcanoes there are several reasons for these islands' supposed existence. Many may be explained by icebergs carrying rocks and moraine sighted in dirty weather. A captain, rightly erring for safety, would report these. Some sightings were more likely the result of a bit too much rum. A few may be deliberate hoaxes: sealers always tried to keep secret the locations of good sealing discoveries and some of them may not have been adverse to sending competitors on wild goose chases. One island was probably added to embellish a book by an author who was known as 'the greatest liar in the Pacific'.Getting rid of all these non-existent islands is a problem, and the persistence of some is phenomenal. Swains Island, ordered to be expunged from the charts in 1920, can still be found in a 1995 comprehensive world atlas produced by a well-known publisher.