Britain's Kate, the Duchess of Cambridge signs a book of condolence in the former Nazi concentration camp Stutthof near the town of Sztutowo, 30 kilometers east of the city of Gdansk, Poland, Tuesday, July 18, 2017. The British royal couple is in Poland with their children on a goodwill visit intended to seal friendly ties after Britain leaves the European Union. (AP Photo/Czarek Sokolowski)