Christopher Columbus is the famous explorer known for his voyages in the 15th century under the Spanish flag. Sponsored by King Ferdinand and Queen Isabella, he embarked on four journeys across the Atlantic, starting in 1492. Columbus aimed to find a direct route to Asia by sailing westward but instead encountered the Americas. His expeditions led to extensive European exploration and colonization of the continent, establishing a transatlantic exchange of goods, cultures, and ideas, famously referred to as the Columbian Exchange. However, his voyages also had devastating effects on indigenous populations due to disease and conquest.