Who are three early explorers of antarctica?

1. Captain James Cook: In 1773, Captain James Cook became the first explorer to cross the Antarctic Circle during his second voyage of exploration in the Pacific Ocean. However, he did not sight the Antarctic mainland.

2. Fabian Gottlieb von Bellingshausen: A Russian naval officer and explorer, Fabian Gottlieb von Bellingshausen, led an expedition to Antarctica in 1819-1821. During this expedition, he and his crew became the first to sight the Antarctic mainland on January 27, 1820.

3. Charles Wilkes: Charles Wilkes, an American naval officer, led the United States Exploring Expedition from 1838 to 1842. He charted parts of the Antarctic coast, especially in the area around the Ross Sea and discovered the Wilkes Land region. Wilkes's expedition was significant in contributing to the early mapping of Antarctica.