Two hundred years since the discovery of Antarctica, the frozen continent is known as a hotbed of scientific exploration and a place of adventure and icy peril. But who really discovered the new continent? That depends on how you define “discovered.” The fateful spotting could be attributed to a Russian expedition on January 27, 1820—or a British one just three days later.

By the early 19th century, explorers had been on the hunt for a massive southern continent they called Terra Australis Incognita (“unknown southern land”). This vast landmass, it was thought, would “balance out” the land in the Northern Hemisphere. But early attempts to find the continent had flopped. Captain James Cook had spent three years looking for it during