What was the Berlin Wall, and why did it fall?

After World War II, Germany and Berlin were each divided among the Allied powers, leaving West Berlin as an enclave of the Western-aligned Federal Republic sitting inside Soviet-aligned East Germany. Through the 1950s, millions of East Germans left through Berlin, disproportionately the young and skilled, which the East German state could not sustain. On August 13, 1961, it sealed the border overnight with barbed wire, replaced over time by a concrete wall with guard towers, a mined and patrolled death strip, and orders to shoot those attempting to cross. Families were separated with no notice. At least 140 people are documented as having died at the Wall, with higher estimates for the inner German border overall.

The Wall stood for 28 years as the most legible symbol of the Cold War division of Europe. Its end came within a broader collapse: Gorbachev's reforms in the Soviet Union, the refusal to intervene militarily as Eastern European states liberalized, Hungary opening its border with Austria in the summer of 1989, and sustained mass demonstrations across East Germany in the autumn, particularly the Monday protests in Leipzig.

The immediate opening was partly accidental. On November 9, 1989, an East German official announced new travel regulations at a press conference and, when asked when they took effect, answered that as far as he knew, immediately. The broadcast sent crowds to the checkpoints, and overwhelmed guards without clear orders eventually opened the gates rather than use force. Berliners crossed freely and began breaking the Wall apart that night. German reunification followed on October 3, 1990. Fragments of the Wall are displayed around the world, and its route through Berlin is now marked by a line of cobblestones through the city.