Magellan's reason for cricumnavigating the globe was to prove that the Spice Islands were Spanish property. Magellan was the first person to circumnavigate the globe. He saild out on September 20th, 1519 with a crew of 237 and five ships. Sadly while stopped in the Phillippines Magellan died. His crew returned with only one ship, and eighteen crew members.
Vasco da Gama set out for his voyage to India on July 8th, 1497. He sailed for Portuguese exploration. He was equipped with four ships and a crew--who were mostly convicts.After making a stop in Malindi, Africa, he was accompanied by Ahmad Ibn Majid the rest of the voyage. Then on May 20th, 1498, they had reached India.
Christopher Columbus was originally from Portugal. In attempt to sail for Portugal, he sailed for Spain istead. He sailed for Spain because Portugal didn't not want to fund his voyage. Upon reaching the West Indies in 1492, he returned an additional three times, making his total voyages--four times.
Dias was the first European man to round the tip of Africa. He sailed for Portugal. By making this accomplishment he opened of Portugal's trade ties with India. Dias inspired Christopher Columbus to sail and find a different route to India for trade.
In 1405, Zheng He, was chosen to lead the biggest sea exploration that existed. He conducted seven fleets during this time of his exploration. He visisted 37 countries. In 1413 Zheng He made his most ambitious voyage. His many voyages sadly ended in 1433, when he passed.