The Berlin Wall was built by the Soviet Union in 1961 to prevent people from escaping from East Berlin to West Berlin. The wall was a concrete structure that was over 100 miles long and it had barbed wire on top. The wall was guarded by soldiers and it was illegal for anyone to try to cross it.
The Berlin Wall was a symbol of the Cold War because it represented the division between the United States and the Soviet Union. The wall was a reminder that the two superpowers were on the brink of war and that they were only preventing a nuclear war because of the threat of mutually assured destruction.
The Berlin Wall was finally torn down in 1989, and the city of Berlin was reunited. The fall of the Berlin Wall was a symbol of the end of the Cold War and the beginning of a new era of cooperation between the United States and the Soviet Union.