Ernest Shackleton had already made a name for himself as an intrepid explorer, having reached a record southern latitude on his Antarctic expedition of 1907-1909, when he set sail on the Endurance in 1914.

The South Pole had been conquered a few years prior by Roald Amundsen, so Shackleton set a more ambitious goal: Land on Antarctica and cross 1,800 miles over the entire continent, an endeavor he named the Imperial Trans-Antarctic Expedition.

With a support ship sailing to the far side of the continent to lay supply caches for the back end of the crossers’ journey, Shackleton took a hand-picked crew of 28 (including one stowaway, a spurned applicant) from Buenos Aires to South Georgia Island and into the frozen Weddell Sea.