“The past is never dead; it’s not even past,” wrote William Faulkner, in a maxim that seems particularly apt whenever people begin arguing over the design of historical monuments. This exhibition of proposed and actual memorials by four German artists concentrates—of course—on the legacy of Nazism but also includes some proposals for a World Trade Center monument. These are less interesting for various reasons, including the moral simplicity of the issue—it’s us vs. them, not us vs. us—and the attempts to somehow retain the form of the twin towers (widely unloved until they were attacked). Horst Hoheisel and Andreas Knitz’s designs for Holocaust-related memorials, both built and unbuilt, are much more resonant. At Buchenwald, a simple plate inscribed with the nationalities of the victims is kept at a constant 98.6 degrees, the temperature of humanity. In place of the Aschrott Fountain, destroyed in 1939 because a Jewish businessman had financed it, a facsimile was installed, but upside down and underground, so that it’s both present and absent. In the courtyard of a state archives building, the ground was paved with “crushed history”—pieces of a Gestapo barracks and prisons that were demolished and shredded. Hoheisel and Knitz also suggested pulverizing Berlin’s Brandenburg Gate, a proposal that was rejected. Yet the most eloquent piece (pictured) incorporates the landmark without altering its form: It simply projects a photograph of Auschwitz’s notorious gate onto the Brandenburg, symbolizing what Hoheisel calls Germany’s “broken identity” while uniting empire and infamy. The show is on view from 9 a.m. to 5 p.m. Mondays through Thursdays, and from 9 a.m. to 3 p.m. Fridays, to Friday, May 20, at the Goethe-Institut’s Gallery, 812 7th St. NW. Free. (202) 289-1200. (Mark Jenkins)