Temporary capital of Lithuania during the invasion of Poland, to Lithuania according to the Soviet–Lithuanian Mutual Assistance Treaty. Since then Vilnius has been the capital of the Lithuanian SSR and then independent Lithuania. Lithuania refused to have diplomatic relations between Poland and Lithuania until the ultimatum of 1938. Railroad traffic, telegraph lines or even mail could not cross the Polish–Lithuanian border. Lithuania continued to declare Vilnius as its capital in all official documents, including the constitution. Since the city was controlled by Poland, all Lithuanian authorities were transferred to the city of Kaunas, which became the seat of the government. To reconcile reality with
Centennial of the Restored State of Lithuania of Independence of Lithuania, which proclaimed the restoration of an Independent State of Lithuania, creating a modern state. During World War II, Lithuania was forcibly occupied and annexed by the Soviet Union in 1940, followed by Nazi Germany in 1941, and again by the Soviets in 1944 as one of its constituent republics. During the late 1980s and the dissolution of the Soviet Union, Lithuania fought to restore its independence which culminated in the Act of the Re-Establishment of the State of Lithuania signed on 11 March 1990. In order to have every Lithuanian citizen experience the significance of this