PARO, BHUTAN - APRIL 16:  Prince William, Duke of Cambridge and Catherine, Duchess of Cambridge bid farewell at Paro Airport before boarding their flight to Agra for their visit to the Taj Mahal on April 16, 2016 in Paro, Bhutan. The Royal couple are on the final day of a week long visit to India and Bhutan that has taken in cities such as Mumbai, Delhi, Kaziranga, Thimphu and Agra. (Photo by Heathcliff O'Malley-Pool/Getty Images)