Cook Crosses the Antarctic Circle
On his second voyage James Cook’s Resolution and Adventure became the first ships to cross the Antarctic Circle (66.5° S). Blocked by ice, Cook never saw the continent.

William Hodges · Public domain · Source
For centuries Europeans believed a great “unknown southern land” lay in the southern hemisphere. The Royal Navy sent James Cook out again in 1772 to find it, and on 17 January 1773 his ships became the first to cross the Antarctic Circle. He crossed it three times on this voyage, and on 30 January 1774 reached 71°10′ S before endless ice turned him back.
Cook wrote that land might lie beyond the ice, but that it could be neither lived in nor used. He never saw the continent, but his voyage ended the old belief in a habitable southern continent.