King Willem-Alexander, Queen Maxima, Crown Princess Amalia, Princess Ariane, Prince Constantijn, Princess Laurentien, Prince Maurits, Princess Marilene, Prince Bernhard, Princess Annette, Prince Pieter, Princess Anita, Prince Floris and Princess Aimee attended the celebration of 2023 King's Day in Rotterdam. King's Day is a national holiday in the Kingdom of the Netherlands. Celebrated on 27 April, the date marks the birth of the King.