The Imperial Trans-Antarctic Expedition (1914–17), also known as the Endurance Expedition, is considered the last major expedition of the Heroic Age of Antarctic Exploration. Conceived by Sir Ernest Shackleton, the expedition was an attempt to make the first land crossing of the Antarctic continent. After the conquest of the South Pole by Roald Amundsen in 1911, this crossing from sea to sea remained, in Shackleton's words, the "one great main object of Antarctic journeyings". The expedition failed to accomplish this objective, but became recognised instead as an epic feat of endurance.
Shackleton had served in the Antarctic on Captain Scott's Discovery Expedition, 1901–04, and had led the British Antarctic Expedition, 1907–09. In this new expedition he proposed to sail to the Weddell Sea and to land a shore party near Vahsel Bay, in preparation for a transcontinental march through the South Pole to the Ross Sea. A supporting group, the Ross Sea party, would meanwhile travel to the opposite side of the continent, establish camp in McMurdo Sound, and from there lay a series of supply depots across the Ross Ice Shelf to the foot of the Beardmore Glacier. These depots would be essential for the transcontinental party's survival, as the party would not be able to carry enough provisions for the entire crossing. The expedition required two ships: Endurance under Shackleton for the Weddell Sea party, and Aurora, under Captain Aeneas Mackintosh, for the Ross Sea party.
Endurance became beset in the ice of the Weddell Sea before reaching Vahsel Bay, and despite efforts to free it, drifted northward, held in the pack ice, throughout the Antarctic winter of 1915. Eventually the ship was crushed and sunk, stranding its 28-man complement on the ice. After months spent in makeshift camps as the ice continued its northwards drift, the party took to the lifeboats to reach the inhospitable, uninhabited Elephant Island. Shackleton and five others then made an 800-mile (1,300 km) open-boat journey in the James Caird to reach South Georgia. From there, Shackleton was eventually able to mount a rescue of the men waiting on Elephant Island and bring them home without loss of life. On the other side of the continent, the Ross Sea party overcame great hardships to fulfil its mission. Aurora was blown from her moorings during a gale and was unable to return, leaving the shore party marooned without proper supplies or equipment. Nevertheless the depots were laid, but three lives were lost in the process.