KATOOMBA, AUSTRALIA - APRIL 17:   Prince William, Duke of Cambridge and Catherine, Duchess of Cambridge arrive to visit the Narrow Neck Lookout and observe abseiling by the Mountain Youth Services group in the Blue Mountains on April 17, 2014 in Katoomba, Australia. The Duke and Duchess of Cambridge are on a three-week tour of Australia and New Zealand, the first official trip overseas with their son, Prince George of Cambridge.  (Photo by Phil Noble - WPA Pool/Getty Images)