James Cook was an 18th century British explorer and navigator who rose through the ranks of the Royal Navy. He led three major voyages of exploration and discovery in the Pacific Ocean, mapping coastlines and claiming territory for Britain. Cook's voyages radically changed European understanding of world geography by mapping New Zealand, Australia's eastern coast, and exploring the Antarctic without finding the hypothesized southern continent. Cook was killed in Hawaii during his third voyage while attempting to take a local leader hostage during escalating tensions with islanders.