Romania – 1st of December

Great Union Day (Romanian: Ziua Marii Uniri, also called Unification Day or National Day) is a national holiday in Romania, celebrated on 1 December, marking the unification of Transylvania, Bessarabia, and Bukovina with the Romanian Kingdom in 1918. This holiday was declared after the Romanian Revolution and commemorates the assembly of the delegates of ethnic Romanians held in Alba Iulia, which declared the Union of Transylvania with Romania.