Crown Prince Constantine of Greece dancing with his sister, Princess Irene, at a Greek Society Ball at the Hilton Hotel, Athens, June 10th 1963. (Photo by Keystone/Hulton Archive/Getty Images)
Crown Prince Constantine of Greece dancing with his sister, Princess Irene, at a Greek Society Ball at the Hilton Hotel, Athens, June 10th 1963. (Photo by Keystone/Hulton Archive/Getty Images)