National Day in Belgium is observed every July 21 to commemorate the day in 1831 when Leopold of Saxe-Cobourg swore allegiance to the new Belgian constitution and became the first King of Belgium. The day marks the culmination of a rebellion against Dutch rule by the southern provinces of the United Netherlands, which led to Belgium's de facto independence. Celebrations begin with a Catholic service, Te Deum, held at the Cathedral of Brussels, attended by the King and other dignitaries. In the afternoon, a military parade takes place, passing by the Royal Palace and around the Parc de Bruxelles, the largest park in central Brussels. The festivities conclude with a large fireworks display in the evening at the Parc de Bruxelles.