GDANSK, POLAND - JULY 18:  (NO UK SALES FOR 28 DAYS FROM CREATE DATE)  Catherine, Duchess of Cambridge and Prince William, Duke of Cambridge visit Stutthof, the former Nazi Germany Concentration Camp during day 2 of their Royal Tour of Poland and Germany on July 18, 2017 in Gdansk, Poland.  (Photo by Pool/Samir Hussein/WireImage)