BERLIN -- The tourist buses that come to the Plotzensee Memorial drive down a long, cobbled lane and stop next to a white factory with a big square window.
Plotzensee is a memorial to martyrs of the German resistance against the Nazis. Visitors find themselves looking through the window at workmen painting the cramped, humpbacked caskets which Germans bury their dead.
So the first thing people see at the Plotzensee is a coffin factory.
Small, sad, ironic and oddly appropriate juxtapositions like this abound in Berlin, and a remarkable number of memorials here recall people murdered by one German government or another.
Enemies of the Nazis were hanged, or guillotined, or sometimes just strangled at Plotzensee Prison, their offenses often as slight as listening to Radio London.
Under Berlin's perpetually gray winter sky, the memorial is bleak and grim. There's a flagstone courtyard and a plain stone wall and a stark inscription: "Der Opfern . . . The Sacrifice. The Hitler dictatorship. The years 1933-1945."
A bulky urn stands stoop-shouldered on the edge of the flagstones, like a mourner at the side of a grave. The urn contains earth dug up from all the Nazi concentration camps. And then, beyond the memorial wall, you enter a nondescript brick building, a kind of outhouse, where 2,500 people died.
The death chamber is a simple arched room, whitewashed and cold. Heavy black hooks hang from a beam just below the ceiling. In thirteen hours on a single night in 1943, 186 people were hanged from hooks like these, eight at a time.
Married couples, a Jesuit priest, communists, socialists, a Prussian finance minister, a lord mayor of Liepzig and generals involved in the 1944 plot to assassinate Hitler, all were executed here.
It is still a jail, a juvenile correctional institution surrounded by an industrial park that includes the casket factory. Just beyond the walled courtyard, the gray sky is punctuated by three chimneys, exclamation points in a footnote to the Holocaust.
Straight across the Tiergarten park, in East Berlin, Rosa Luxemburg Platz and Karl Liebknecht Strasse honor radicals killed in 1919 by "Free Corps" troops, discharged soldiers serving the first German Republic.
Ernest Thaelmann Park recalls the man who got 13 percent of the vote in the last election before Adolf Hitler took power. He died in Buchenwald concentration camp.
Rosa Luxemburg Platz and Ernst Thaelmann Park are perhaps more familiar today as stops on the U-Bahn, the subway, than as memorials to heroes of a lost revolution.
Liebknecht, who was dumped into a pond in the Tiergarten, founded the Spartacus League, which became the German Communist Party. A marker under the portico of an old building on Sophienstrasse marks the spot. But Sophienstrasse is nicely gentrified now, a bit artsy-craftsy, and not at all revolutionary.
Luxemburg, Thaelmann and Liebknecht were all Communists honored by Communists and perhaps unfashionable to mourn anywhere nowadays.
But the small garden of crosses by the Reichstag, the old German parliament building, is a memorial to people killed trying to cross the wall that separated East and West Berlin until 1989. And, of course, the Communist heirs of Luxemburg, Liebknecht and Thaelmann built that wall.
The Jewish dead haunt the streets everywhere. At the site of the long-vanished Letzowerstrasse synagogue, a massive monument of stone and steel takes the form of a boxcar and its doomed cargo, a symbol of the transports to the death camps.
Cut into a gaunt steel pylon rising behind the boxcar monument are the dates and numbers of the transports: "31. 1 Marz 1943. 1736 Juden nach Auschwitz . . . "
The pylon stands right in front of the entrance to a children's playground. A fair amount of what may be childish graffiti are scrawled across the base of the pylon. On the memorial plaque nearby someone perhaps not so childish has chalked the letters J-U-D, Jew.
The city's first Jewish cemetery -- Der Alter Judische Friedhof -- has been restored into a grassy, tree-shaded memorial park. The Nazis not only demolished the tombstones, they dug up the dead.
But the park that was the old cemetery is now so pleasant that neighborhood people like to walk their dogs there. Berliners love their dogs. They treat them very well.