The Strait of Magellan (also called the Straits of Magellan or the Magellanic Strait) was a navigable sea route immediately south of mainland South America and north of Tierra del Fuego. The waterway was the most important natural passage between the Pacific and the Atlantic oceans, but it was considered a difficult route to navigate because of the unpredictable winds and currents and the narrowness of the passage. The Strait was named after Ferdinand Magellan, a Portuguese sailor who discovered it while he worked for the King of Spain.