Captain James Cook is known for his voyages to the Pacific Ocean and mapping its islands and coastlines.

Background:
Captain James Cook was a British explorer and navigator who made three voyages to the Pacific Ocean during the 18th century. He is regarded as one of the greatest explorers and navigators in history due to his significant contributions to the mapping of the Pacific region.

Voyages:
1. First Voyage (1768-1771):
- Cook's first voyage was aboard the HMS Endeavour, which set sail in 1768.
- His primary mission was to observe the transit of Venus across the sun and to search for the hypothetical southern continent known as Terra Australis.
- During this voyage, Cook mapped the coast of New Zealand and discovered and charted the eastern coast of Australia, claiming it for the British Crown.

2. Second Voyage (1772-1775):
- Cook's second voyage was aboard the HMS Resolution and the HMS Adventure.
- This voyage aimed to find the hypothetical southern continent and to explore the Pacific further.
- Cook became the first European to cross the Antarctic Circle and circumnavigated Antarctica, disproving the existence of a large southern continent.
- He also visited islands in the Pacific such as Tahiti, Easter Island, and the Marquesas Islands, and mapped their coastlines.

3. Third Voyage (1776-1779):
- Cook's third and final voyage was aboard the HMS Resolution and the HMS Discovery.
- His main objective was to find the Northwest Passage, a sea route connecting the Atlantic and Pacific Oceans.
- Although he did not find the Northwest Passage, Cook explored the Pacific extensively, including the Hawaiian Islands, the Aleutian Islands, and the Bering Strait.
- During this voyage, Cook was killed in a conflict with the indigenous people of Hawaii.

Legacy:
Captain James Cook's voyages greatly contributed to the scientific knowledge of the Pacific region and the mapping of its islands and coastlines. His meticulous charting of previously uncharted territories helped shape the modern understanding of the Pacific Ocean and its islands. Cook's expeditions also paved the way for future explorations and colonization in the region. He is remembered as one of the most influential explorers of all time.