On July 21st, Belgians celebrate the National Day, which commemorates an event on 21 July 1831 in which Leopold of Saxe-Cobourg swore allegiance to the new Belgian constitution, thus becoming the nation’s first monarch. The king’s vow marked the start of the independent state of Belgium under a constitutional monarchy and parliament.
The day typically starts with a Catholic Te Deum service in Cathedral of Brussels attended by the King and other dignitaries. In the afternoon, the Belgian Army and police are reviewed by the King, and parade past the Royal Palace and around the Parc de Bruxelles. There is a flypast by the air force. The military, civil defense and emergency services and other government departments typically have stalls in the nearby Place Poelart, Rue de la Régence, Place Royale and surroundings, which explain their roles to the public.
Many notable buildings in Brussels that are usually closed are open to the public on National Day. A variety of entertainment is presented in several venues around the city, particularly in the city center. The festivities end with a large fireworks display in the Parc de Bruxelles.