German reunification
German reunification of 1990 (3 October 1990, (Frankfurt Region - why) The East German government started to falter in May 1989, when the removal of Hungary's border fence with Austria opened a hole in the Iron Curtain. It caused an exodus of thousands of East Germans fleeing to West Germany and Austria via Hungary. The Peaceful Revolution, a series of protests by East Germans, led to the GDR's first free elections on 18 March 1990, and to the negotiations between the GDR and FRG that culminated in a Unification Treaty. Other negotiations between the GDR and FRG and the four occupying powers produced the so-called "Two Plus Four Treaty" (Treaty on the Final Settlement with Respect to Germany) granting full sovereignty to a unified German state, whose two parts were previously bound by a number of limitations stemming from their post-World War II status as occupied regions.
The united Germany is not a successor state, but an enlarged continuation of the former West Germany. As such, the enlarged Federal Republic of Germany retained the West German seats in international organizations including the European Community (later the European Union) and NATO, while relinquishing membership in the Warsaw Pact and other international organizations to which only East Germany belonged. It also maintains the United Nations membership of the old West Germany.