Which explorer conducted a total of four voyages to the Americas and established the Columbian Exchange and trans-Atlantic slave trade?

The explorer which conducted a total of four voyages to the Americas and established the Columbian Exchange and trans-Atlantic slave trade was Christopher Columbus. He was an Italian navigator and made four trips across the Atlantic Ocean, where he sparked the race for Spanish settlements in the Americas. The Columbian Exchange is named chiefly after him, as it is the exchange of animals, plants, ideas and culture which happened between Africa, Europe and the Americas (primarily).