Britain's Prince William, center, his wife Kate, Duchess of Cambridge and Prince Harry arrive for an event at the memorial garden in Kensington Palace, London, Wednesday, Aug. 30, 2017. Princes William and Harry are paying tribute to their mother, Princess Diana, on the eve of the 20th anniversary of her death by visiting the Sunken Garden to honor Diana's work with charities. (AP Photo/Kirsty Wigglesworth)