Magellan, Strait of, a channel near the southern tip of South America. The strait, 350 miles (560 km) long, links the Atlantic Ocean with the Pacific, and separates mainland Chile from Tierra del Fuego, an island group. Punta Arenas is the main city on the strait. Ferdinand Magellan of Portugal discovered the strait in 1520. It was an important shipping route until the Panama Canal was opened in 1914.