Final answer:
Ferdinand Magellan, a Portuguese navigator who sailed for Spain in 1519, is the explorer whose fleet was the first to circumnavigate the world.
Step-by-step explanation:
The explorer referred to in the question is Ferdinand Magellan. He was a Portuguese navigator who sailed for Spain in 1519. Magellan embarked on his journey with five ships, but tragically, he was killed along the way, and only one ship, the Victoria, made it back to Spain. This expedition is considered the first circumnavigation of the world.
Learn more about Ferdinand Magellan