The Arctic and Southern Oceans at the far ends of our planet have been enormously attractive for explorers and adventurers. It is a brief history of discovery with the first crossing of the Arctic Ocean during 1893-95 by Norse explorer Fridtjof Nansen's Fram Expedition. Until that time, many experts believed there was a central land mass surrounding the North Pole. To the south, the first sighting of the Antarctic continent was made in 1820 by the Russian Fabian Gottlieb von Bellingshausen. Until that sighting, many postulated that there was no land mass there.
Almost all of the pre-World War II explorations of the polar oceans were for commercial purposes (i.e., whaling and sealing), advancing territorial claims, or pure adventure. Systematic scientific research was not emphasized. It was only after the war that fundamental scientific research began to dominate work in these areas. New platforms such as aircraft, satellites, and nuclear-powered submarines helped make these least-known oceans increasingly transparent.