On 20 May 1916, Ernest Shackleton, Frank Worsley, and Tom Crean reached Stromness, a whaling station on the north coast of South Georgia. They had been walking for 36 hours, in life-threatening conditions. They did not talk about it at the time, but weeks later all three men reported an uncanny experience during their trek: a feeling that often there were four, not three" men on their journey. The "fourth" that accompanied them had the silent presence of a real person, someone walking with them by their side. Encounters such as these are common in extreme survival situations: guardian angels, guides, or even Christ-like figures have often been reported. We know them now as "third man" experiences, following a line in TS Eliot's poem, The Wasteland: "Who is the third who walks always beside you? When I count, there are only you and I together. But when I look ahead up the white road, there is always another one walking beside you." In his book The Third Man Factor, John Geiger collects together a wide range of third man stories, including accounts from mountaineers, sailors, and survivors of terrorist attacks. They all involve a strong impression of a felt presence ... which will often feel as if it has a spiritual or guiding purpose.