EDITH SHEFFER is assistant professor of history at Stanford University and author of "Burned Bridge: How East and West Germans Made the Iron Curtain" (Oxford University Press, September 2011).

Fifty years ago, on August 13, 1961, the Berlin Wall went up overnight. It immediately became a chilling icon of political repression. Yet on its semicentennial it is time we recognize how the wall's strength came as much from concrete as from the society that supported its creation. As fortified borders proliferate around the world today, such as those between the U.S. and Mexico and the Israeli "security fence," Germany's story warns us that walls can permeate the culture with enduring and even deadly consequences.

As East Germany built the Berlin Wall to stem the mass flight of East Germans to the West, it became a flash point of the Cold War standoff and of human tragedy, with daring escapes, at least 136 deaths, and divided communities, friends, and families.

But the Berlin Wall was only the final and most notorious portion of Germany's Iron Curtain. Along the rest of the 1,393 kilometer border between East and West Germany, formidable physical and emotional divides had been growing since the end of World War II.

Governments and civilians in both East and West had improvised this Iron Curtain. In the late 1940s, for example, the U.S. Army increased border security and built barriers to quell rampant Soviet rape and violence. Meanwhile, western Germans won additional forces and legislation to keep out East German smugglers, undocumented workers and migrants....