The document summarizes the history of the Berlin Wall, including its construction in 1961 by East Germany to prevent emigration to West Berlin, details of its physical structure, and statistics on deaths that occurred from people trying to cross over. It then discusses internal and external pressures that led to the Wall's fall in 1989, including Gorbachev's policies of perestroika and glasnost that reduced Soviet control over satellite states. The document concludes with Germany being reunified in 1990.