These were some of the most evil 11 acres in Germany, a place where Nazi leaders hatched plans to terrorize millions as casually as you might send an email. Heinrich Himmler had an office there. So did Adolf Eichmann, the “architect of the Holocaust.” It was there that, in a matter of months, German democracy began to crumble.Sixty-five years on, Berlin has transformed the Topography of Terror, a cluster of buildings that housed the Gestapo, the SS, and other police agencies from 1933 to 1945, into an exhibition space trained on the elaborate workings and aftermath of the Third Reich. The center opens this week. Its the sites first permanent landmark, after more than 20 years of fits and starts, and the problem it confronts is a vexing one for architects: How do you document evil without building a monument to it?