What explorer learned he sailed more than three times as far as Columbus thought he did?

The explorer who learned he had sailed more than three times as far as Columbus thought he did is Ferdinand Magellan. During his expedition from 1519 to 1522, Magellan circumnavigated the globe, demonstrating the vastness of the Earth and the true distances involved. His journey revealed that the world was much larger than Columbus had estimated, as Columbus had believed he had reached the Indies when, in fact, he had encountered the Americas. Magellan's voyage provided a clearer understanding of global geography.