Teufelsberg, Devil’s Mountain, is an 80-meter hill in what was West Berlin. It is an artificial mound, built in accordance with post-World War ii Allied directives on Berlin debris during the city’s 20-year reconstruction. The amount of rubble piled up there is estimated at 12 million cubic meters, the equivalent of some 400,000 buildings. There is nothing unique about Teufelsberg; numerous mounds of the kind exist in Germany and in other European cities devastated by the war. What’s special here is what’s buried underneath: a Nazi university conceived by Albert Speer...