The famous explorer known for their voyages to Polynesia in the 18th century is James Cook. Cook was a British navigator and cartographer whose expeditions in the South Pacific, including Hawaii, significantly increased European knowledge of the region. His journeys revolutionized maritime navigation and geography, mapping many previously uncharted territories. Cook's interactions with indigenous peoples and his documentation of their cultures were notable, though they often had lasting consequences for those societies. His explorations paved the way for further European exploration and colonization, significantly influencing the history of Polynesia and the Pacific islands.