BELGRADE, SERBIA - MARCH 16: (L-R) Hereditary Prince Peter Karadjordjevic, Katherine Karadjordjevic, Crown Princess of Yugoslavia, Prince Charles, Prince of Wales and Alexander Karadjordjevic, Crown Prince of Yugoslavia speak during the first day of a two day visit to Serbia on March 16, 2016 in Belgrade, Serbia. (Photo by Srdjan Stevanovic/Getty Images)

BELGRADE, SERBIA - MARCH 16:  (L-R)  Hereditary Prince Peter Karadjordjevic, Katherine Karadjordjevic, Crown Princess of Yugoslavia, Prince Charles, Prince of Wales and Alexander Karadjordjevic, Crown Prince of Yugoslavia speak during the first day of a two day visit to Serbia on March 16, 2016 in Belgrade, Serbia. (Photo by Srdjan Stevanovic/Getty Images)