The German Democratic Republic (GDR; German: Deutsche Demokratische Republik or DDR), informally known in English as East Germany, was a socialist state established by the Soviet Union in 1949 out of the Soviet zone of occupied Germany, including East Berlin of the Allied-occupied capital city. The GDR had an area of 107,771 km2 (41,610 mi2), bordering Czechoslovakia to the south, West Germany to the south and west, Poland to the east, and the Baltic Sea to the north. East Germany ceased to exist when its federal states were re-established and acceded to the Federal Republic of Germany on 3 October 1990 (see German reunification).
East Germany has often been described as one of several satellite states of the Soviet Union. Some East Germans saw the state as illegitimate, artificial, a Stalinist puppet regime, and they opposed the dominance of the Socialist Unity Party while viewing West Germany as more socially and politically 'attractive'. Some East Germans regularly referred to the Socialist Unity Party as "the Russian party". The combination of the state's perceived illegitimacy by East Germans and economic problems resulted in 2.7 million East Germans violating the DDR ban on leaving the country by going to West Germany in the 1950s. Frontier barriers were constructed to prevent further depopulation caused by emigration to West Germany. These barriers held no military value beyond migration control as they were too weak to withstand a potential NATO invasion. The most prominent frontier barrier was the Berlin Wall, constructed in 1961, which finally closed the loop hole in the East German border between East Berlin and West Berlin. Those who did attempt to flee across the border risked their lives as East German Border Guards were authorised to use lethal force against escapees, resulting in over 100 deaths. In 1989 a non-violent revolution called for the end of the East German communist government. The Soviet Union, under the reformist leadership of Mikhail Gorbachev, refused to intervene on the basis of his policy to de-escalate the Cold War and let East Germany resolve its own crisis. The revolution toppled the communist government and the country soon reunited with West Germany, bringing to an end over 40 years of division and reunifying the nation into a single Germany.