Commanding HMS Resolution and Adventure, Cook crossed 66°33' south latitude, disproving theories of a temperate southern continent suitable for colonization. His voyage mapped vast stretches of the Southern Ocean and dispelled centuries of speculation about Terra Australis.
European geographers had long speculated about a great southern landmass, Terra Australis Incognita, imagined as a fertile counterweight to the continents of the north. James Cook's second voyage was tasked explicitly with settling the question once and for all, and on January 17, 1773 his ships crossed the Antarctic Circle for the first time in recorded history.
Cook pushed his crews through brutal cold and dense fog, navigating among icebergs that could crush a wooden ship without warning. He never sighted the Antarctic continent itself, turning back before reaching land, but his voyage proved that any southern continent, if it existed, lay buried under ice far too hostile for the settlements earlier theorists imagined.
The expedition permanently altered the map of human ambition in the far south, discouraging further colonization fantasies while whetting scientific curiosity that would eventually draw explorers like Shackleton and Amundsen a century later. Cook's meticulous logs and charts remained the standard reference for Antarctic waters for generations.