This weekend, the world celebrates the 30th anniversary of the fall of the Berlin Wall. On November 9, 1989, East Germans began picking at the wall with hammers, picks – even their bare hands – until the mammoth structure that had divided the city for the past 28 years lay in ruins.

Here are five facts you need to know about the Berlin Wall.

1. The Berlin Wall grew out of a settlement made at the end of World War II at Yalta and Potsdam. The Allies agreed to divide Germany into four regions occupied by the United States, the UK, France, and the USSR. Berlin, which lay entirely inside the Soviet region, had been similarly divided. Until 1961, people regularly passed from East Germany (known as the German Democratic Republic, or DDR) to West Germany (the Federal Republic of Germany, or DBR) – too regularly for the Communist authorities. Up to one-sixth of the population of East Germany, nearly 3.5 million people, fled into West Germany – reaching 1,000 a day by 1961. To stop the emigration of workers from the workers’ paradise, Nikita Khrushchev gave Socialist Unity Party General Secretary Walter Ulbricht permission to erect a barrier on the border.

2. Creation of the Berlin Wall began overnight on August 12-13, 1961. The original barrier consisted of coiled barbed wire and concrete blocks. The Berlin Wall ran 96 miles in length (27 miles within Berlin), and two walls rose between 11 and 15 feet high. Between them was a 160-foot “death strip.” The wall included 302 watchtowers, 20 bunkers, 55,000 land mines, 259 dog runs, and machine guns activated by tripwires. Initially, those with the proper documentation could cross through three checkpoints: “Checkpoint Alpha” in Helmstedt, “Checkpoint Bravo” in Dreilinden, and “Checkpoint Charlie” in Friedrichstrasse. East German officials called the wall the “Antifaschistischer Schutzwall,” telling citizens that the USSR erected the barrier to keep fascists out. But few were fooled by the Soviets’ motivation.

3. No fewer than 327 people died trying to cross the Berlin Wall into West Germany, 10 percent of whom were women. Another 5,000 people were captured trying to escape over (or sometimes, under) the wall.

4. The events that led to the fall of the Berlin Wall unfolded without a government order. During a routine press conference on November 9, 1989, government spokesman Günter Schabowski misread notes that indicated the government would allow East Germans to cross into West Berlin “immediately, without delay.” The Politburo intended the announcement to be released the next morning – and it only authorized people to apply for a travel visa. Guards, who now found themselves besieged by hundreds of thousands of East Germans eager to cross, received no orders on how to respond. Harald Jäger, who guarded the checkpoint at Bornholmer Strasse, ordered that the barrier be opened. Soon, people began streaming into West Berlin.

5. Communists and Soviet apologists attempted throughout the Cold War to equate the Berlin Wall with U.S. immigration policy. Ronald Reagan rebuffed these notions when he arrived in Berlin on June 11, 1982. “The Iron Curtain wasn’t woven to keep people out; it’s there to keep people in,” he said. “The most obvious symbol of this is the Berlin Wall.” Just six days later at the United Nations, he would call the wall “a grim, gray monument to repression.” And on June 12, 1987, he delivered his speech at the Brandenburg Gate demanding, “Mr. Gorbachev, tear down this wall.”

(Photo: Public domain.)