Ferdinand Magellan was the first (at least his crew) to successfully lead an expedition to circumnavigate the world. (he died on the voyage, but ~3 sailors made it back i believe, forgot the number of sailors, but very little)
His exploration was the first to circumnavigate the globe, proving the Earth was not flat. He is credited for circumnavigating the globe; however, he was killed by head hunters somewhere around the Philippines/Southeast Asia (I think...).
