Dutch King Willem-Alexander and his wife Queen Maxima wave to the crowd with their daughters Crown Princess Catharina-Amalia (L), Princess Alexia (R) and Princess Ariane (C) on the balcony of the Royal Palace in Amsterdam April 30. The Netherlands is celebrating Queen's Day on Tuesday, which will also mark the abdication of Queen Beatrix and the investiture of her eldest son Willem-Alexander. - Reuters/Kevin Coombs