Britain's Prince William, Duke of Cambridge (C) and his wife Kate, the Duchess of Cambridge, and Hamburg's mayor Olaf Scholz (L) visit the Elbphilharmonie concert hall in Hamburg, northern Germany, on July 21,2017.
 The British royal couple are on the last stage of their three-day visit to Germany. / AFP PHOTO / POOL / Christophe Gateau        (Photo credit should read CHRISTOPHE GATEAU/AFP/Getty Images)