Angry West Berliners demonstrated against the division of their city, a divide that separated many families. The allies were unsure how to react -- their rights within Berlin had not been challenged by the Soviets. But a border crossing confrontation prompted U.S. Gen. Lucius Clay to bring up tanks. The Soviets responded with their own show of force. Both sides later withdrew their armor.

Many in the East, meanwhile, risked death to flee across the Wall. Within the first year, 50 Germans died trying to cross to the West. One of them, 18-year-old Peter Fechter, bled to death in the no-man's land between East and West, in front of outraged West Berliners.

In 1963, Kennedy visited West Berlin -- telling its residents that all free people were citizens of Berlin and "therefore as a free man, I take pride in the words, 'Ich bin ein Berliner.'"

Yet for the next three decades, the Wall remained a symbol of the Cold War's cruelty and Europe's division. Its message was a bitter one: Whatever happened beyond that line, the West might lament, but would not interfere.