Britain's Prince William, Duke of Cambridge, (L) and polar explorer Henry Worsley, pose with a Union flag at Kensington Palace in London on October 19, 2015. Worsley will undertake the 2015/16 Shackleton solo challenge starting in November, and attempting to undertake Sir Ernest Shackleton's unfinished journey to the South Pole from the Weddell Sea.   AFP PHOTO / JOHN STILLWELL / POOL        (Photo credit should read JOHN STILLWELL/AFP/Getty Images)