The East German government had begun sealing off the East German border to West Germany as early as 1952, making it increasingly dangerous to flee directly to the West. Many chose to take advantage of the last means of escape, and reached West Germany by crossing the sector borders through to West Berlin.

In the early hours of August 13, 1961, Berliners living in the east of their city were awakened by the moaning of heavy machinery rolling hastily through their streets toward the boundary that separated the eastern and western parts of their city.

Confounded citizens looked on as East German soldiers dug holes and tore up sidewalks, making way for barbed wire that would close off the dividing line. Armed troops manned the crossing points between the two sides and, by morning, a ring of Soviet soldiers surrounded the city. Overnight, the right to pass between the two sections of Berlin had ended.

Running through cemeteries and canals, criss-crossing through the city streets, the Berlin Wall was a shocking representation of the Iron Curtain that separated all of Europe between competing ideologies.

Berlin was always the centerpiece of the Cold War and on multiple occasions very nearly the front line of real combat.