Austria-Hungary collapsed after World War I, and the subsequent Treaty of Trianon established Hungary's current borders, resulting in the loss of 71% of its territory, 58% of its population, and 32% of ethnic Hungarians. Following the tumultuous interwar period, Hungary joined the Axis Powers in World War II, suffering significant damage and casualties. Postwar Hungary became a satellite state of the Soviet Union, leading to the establishment of the Hungarian People's Republic. Following the failed 1956 revolution, Hungary became a comparatively freer, though still repressive, member of the Eastern Bloc. The removal of Hungary's border fence with Austria accelerated the collapse of the Eastern Bloc, and subsequently the Soviet Union. On 23 October 1989, Hungary became a democratic parliamentary republic. Hungary joined the European Union in 2004 and has been part of the Schengen Area since 2007.