Prince William and Catherine lay a wreath at Plac Solidarnosci in Gdansk, Poland. Agencja Gazeta/Renata Dabrowska/via REUTERS
Prince William and his wife Catherine are welcomed by the Polish President Andrzej Duda and his wife Agata Kornhauser-Duda at the Presidential Palace in Warsaw. Agencja Gazeta/Slawomir Kaminski via REUTERS
Prince William, the Duke of Cambridge, his wife Catherine, The Duchess of Cambridge, Prince George and Princess Charlotte arrive at Tegel airport in Berlin, Germany, July 19, 2017. REUTERS/Kay Nietfeld/POOL
Catherine, The Duchess of Cambridge and Agata Kornhauser-Duda wait as Polish president Andrzej Duda and Prince William, the Duke of Cambridge light candles at the Warsaw Rising Museum in Warsaw, Poland July 17, 2017. REUTERS/Kacper Pempel
Prince George arrives at Tegel airport in Berlin, Germany, July 19, 2017. REUTERS/Fabrizio Bensch
Prince William, the Duke of Cambridge and Catherine, The Duchess of Cambridge sign the book of visitors at the museum of former German Nazi concentration camp Stutthof in Sztutowo, Poland July 18, 2017. REUTERS/Kacper Pempel
Prince William, the Duke of Cambridge, his wife Catherine, The Duchess of Cambridge, Mayor of Berlin Michael Mueller and his daughter Nina pose at Brandenburg Gate in Berlin, Germany, July 19, 2017. REUTERS/Fabrizio Bensch
Prince William and Catherine at Plac Solidarnosci in Gdansk, Poland. Agencja Gazeta/Renata Dabrowska/via REUTERS
Prince William, the Duke of Cambridge and his wife Catherine, The Duchess of Cambridge visit Brandenburg Gate in Berlin, Germany, July 19, 2017. REUTERS/Axel Schmidt
Prince William, Catherine, and Lech Walesa visit the European Solidarity Centre in Gdansk, Poland. Agencja Gazeta/Renata Dabrowska/via REUTERS
Prince William and Catherine visit the European Solidarity Centre in Gdansk, Poland. Agencja Gazeta/Renata Dabrowska/via REUTERS
German Chancellor Angela Merkel chats with Prince William, the Duke of Cambridge and his wife Catherine, The Duchess of Cambridge, at the Chancellery in Berlin, Germany July 19, 2017. REUTERS/Axel Schmidt
Catherine, The Duchess of Cambridge greets people, at Brandenburg Gate in Berlin, Germany, July 19, 2017. REUTERS/Fabrizio Bensch
Catherine, The Duchess of Cambridge greets people at the central market square in Gdansk, Poland July 18, 2017. REUTERS/Bogdan Popescu
Will and Kate's pre-Brexit charm tour
Prince William and his wife Kate shore up relations with European Union countries before Britain leaves the bloc.