LUXEMBOURG - MAY 11:  Catherine, Duchess of Cambridge with Princess Stephanie of Luxembourg and Prince Guillaume of Luxembourg visit the Drai Eechelen Museum during a one day visit on May 11, 2017 in Luxembourg. The Duchess will attend a series of engagements to celebrate the cultural and historic ties between the UK and Luxembourg and the official commemoration of the 1867 Treaty of London, which confirmed Luxembourg's independence and neutrality.  (Photo by Pool/Samir Hussein/Samir Hussein/WireImage)