Which explorer led the expedition that began the first circumnavigation of Earth?

Ferdinand Magellan led the expedition that began the first circumnavigation of Earth.

The expedition sailed from Spain in 1519 with five ships seeking a westward route to the Spice Islands. Magellan's fleet crossed the Atlantic, passed through the strait now called the Strait of Magellan, and entered the Pacific Ocean, which he named for its apparently calm waters.

Magellan was killed in the Philippines in 1521 before the voyage was completed. Juan Sebastián Elcano then took command of the surviving ship, Victoria, which returned to Spain in 1522. For this reason, Magellan led the expedition, but Elcano completed the circumnavigation.

Only one ship and 18 of the original crew returned. The voyage provided powerful practical evidence that the world's oceans were connected, although educated Europeans already knew Earth was spherical. It also revealed the immense size of the Pacific and exposed major errors in contemporary estimates of Earth's dimensions.