East Germany

In the years immediately following the end of World War II, the fate of the German nation would be determined by the victors of the conflict: Great Britain, the United States, the Soviet Union, and France. At the Potsdam Summit Conference, the four broke Germany into four separate spheres of influence, each controlled by one of the Allied victors. When the three western zones consolidated into the Federal Republic of Germany in 1949, the German Democratic Republic - more commonly known as East Germany - was established as a satellite state of the Soviet Union in the same year.
East Germany was unique in that it had a bastion of western culture within its borders - West Berlin. Rather than allow the country's most prosperous city to fall squarely within the confines of a Soviet territory, the Allied powers agreed to divide the city of Berlin in much the same way that the nation of Germany was divided. This resulted in the creation of West Berlin - formed from the combination of the three western sectors - directly in the middle of a Soviet territory. While East Germany was the most successful economy in the Soviet Eastern Bloc, that did not prevent people from trying to flee to western-controlled territories; this was especially true with emigration to West Berlin.
In 1961, the Soviet government responded to this trend by not only fortifying its borders, but also by creating the most iconic symbol of the Cold War: the Berlin Wall. While this barrier would remain in existence for nearly three decades, it would be a combination of factors that would lead to both its fall, as well as to the fall of the Soviet Eastern Bloc in general. By 1989, social revolutions, economic motivators, and changing political forces would all converge to pose an insurmountable challenge to Soviet control in Eastern Europe. The Berlin Wall would quite literally fall that year, and open elections would be held in 1990. The consensus was that the division between the two Germanys should be dissolved, and the country was reunified on October 3, 1990, bringing about the end of the separate nations of East Germany and West Germany.