Roald Engelbregt Gravning Amundsen was a Norwegian explorer of polar regions. He led the Antarctic expedition to discover the South Pole in December 1911 and he was the first expedition leader to reach the North Pole in 1926. He is also known as the first to traverse the Northwest Passage. He disappeared in June 1928 while taking part in a rescue mission. Amundsen, Douglas Mawson, Robert Falcon Scott, and Ernest Shackleton were key expedition leaders during the Heroic Age of Antarctic Exploration.