West Germany was the informal name for what was officially the Federal Republic of Germany (German: Bundesrepublik Deutschland), a country in Central Europe, in the period between its formation on May 23rd 1949 and German reunification on October 3rd 1990. During this Cold War period, the western portion of Germany was part of the Western bloc. The Federal Republic was created during the Allied occupation of Germany after World War II, established from eleven states formed in the three Allied zones of occupation held by the United States, the United Kingdom and France. Its (provisional) capital was the city of Bonn. The Cold War era West Germany is sometimes retrospectively historically designated the "Bonn Republic".
At the onset of the Cold War, Europe was divided among the Western and Eastern blocs. Germany was de facto divided into two countries and two special territories, the Saarland and a divided Berlin. Initially, the Federal Republic of Germany claimed an exclusive mandate for all of Germany, considering itself to be the sole democratically reorganized continuation of the 1871–1945 German Reich. It took the line that the GDR was an illegally constituted puppet state. Though the GDR did hold regular elections, these were neither free nor fair. From the West German perspective, the GDR was therefore illegitimate. Three southwestern states of West Germany merged to form Baden-Württemberg in 1952, and the Saarland joined the Federal Republic of Germany in 1957. In addition to the resulting ten states, West Berlin was considered an unofficial de facto eleventh state. While legally not part of the Federal Republic of Germany, as Berlin was under the control of the Allied Control Council, West Berlin politically aligned itself with West Germany and was represented in its federal institutions.
The foundation for the influential position held by Germany today was laid during the Wirtschaftswunder (economic miracle) of the 1950s when West Germany rose from the enormous destruction wrought by World War II to become the world's third-largest economy. The first chancellor Konrad Adenauer, who remained in office until 1963, had worked for a full alignment with NATO rather than neutrality. He not only secured a membership in NATO but was also a proponent of agreements which developed into the present-day European Union. When the G6 was established in 1975, there was no question as to whether the Federal Republic of Germany would become a member.
Following the collapse of communism in Central and Eastern Europe in 1989, symbolized by the opening of the Berlin Wall, there was a rapid move towards German reunification. East Germany voted to dissolve itself and accede to the Federal Republic in 1990. Its five post-war states (Länder) were reconstituted along with the reunited Berlin, which ended its special status and formed an additional Land. They formally joined the Federal Republic on October 3rd 1990, raising the number of states from ten to sixteen, ending the division of Germany. The reunion did not result in a new country; instead, the process was essentially a voluntary act of accession, whereby West Germany was enlarged to include the additional states of East Germany, which then ceased to exist. The expanded Federal Republic retained West Germany's political culture and continued its existing memberships in international organisations, as well as its Western foreign policy alignment and affiliation to Western alliances like UN, NATO, OECD and the European Union.