I first saw the Berlin Wall in 1971. It was then about 10 years old and was the ugliest human structure I'd ever seen: gray, brutal, pitiless, unyielding. Unlike the walls built around ancient European cities (and the one being proposed for the U.S. border with Mexico), this one was not created to keep people out. It was to keep East Germans in. If they tried to leave the workers' paradise, they must go to the dungeon or the grave. Only Stalinists could have built this most vile symbol, people with hearts and minds made of concrete certainties.