- The Berlin Wall, a concrete barrier dividing West Berlin from East Germany, was built in 1961 by the German Democratic Republic (GDR, East Germany).
- The wall aimed to prevent East Germans from escaping to the West and stemmed the brain drain of skilled workers.
- The construction of the Berlin Wall exacerbated Cold War tensions and nearly led to armed conflict between the United States and the Soviet Union.
- President John F. Kennedy responded by sending additional troops to West Berlin and delivering a speech reaffirming U.S. commitment to the city's freedom.
