A map discovered in 1929 by historians in the Palace of Topkapi, Istanbul. It shows, in remarkably accurate detail, the coastlines of North and South America and the geography of Greenland and Antarctica below their ice sheets. The mapmaker also had accurate knowledge of relative longitudes.
The legend of this map’s production is as follows: Piri Reis, a 16th-century Turkish admiral, was an avid collector of old maps at a time when all maps were somewhat inadequate and charted only coastal waters, which was not surprising. The more maps an admiral had, the more he was able to cross-check them against each other and against his experience, thus improving his navigation. Among Reis’s captives taken in an early 16th century sea battle was a man claiming to have been one of Columbus’s pilots on his epic voyages to the West Indies. He further claimed that Columbus had not sailed west acting only on a hunch but that he had had maps, which were still in his, the captive’s, possession. The admiral appropriated them and used them, together with his other old charts, to construct the Piri Reis map in 1513—the one discovered by 20th-century historians.