His desk, chair and phone are gone but, otherwise, things look the same in the office of Count Claus von Stauffenberg, where he waited to hear his fate on July 20th, 1944.

The aristocratic officer had flown to Hitler’s military headquarters in East Prussia for his third – and final – attempt to kill the Nazi dictator. When he landed back in Berlin, von Stauffenberg was sure the suitcase bomb he’d planted at Hitler’s feet had eliminated its target. It was not Hitler who died on July 20th, however, but Stauffenberg and his co-conspirators, in the courtyard outside his office.

Today's anniversary of the failed plot against Hitler is heavy in historical symbolism, the day when Germany recalls that not everyone in the Third Reich was a dedicated follower of fascism.

But it has taken seven decades for the interest in Nazi resistance to expand beyond the July 20th plot. A remarkable new exhibition in von Stauffenberg’s one-time headquarters, Berlin’s Bendler Block, stitches together for the first time the sprawling, diverse patchwork of Nazi resistance groups around Third Reich Germany.

The exhibition explains who joined the groups, what motivated them and, most interestingly, how the story of their bravery was repressed in the two postwar German states.

Best known are the pockets of resistance inside Germany’s aristocratic families. The July 20th group, for instance, had its roots in the “Kreisau Circle” which met at the Silesian estate of Helmuth James von Moltke. As well as aristocrats, however, the circle attracted union officials, Jesuits and Lutheran pastors and diplomats for treasonous talks about post-Hitler Germany.

There were student movements, like Munich's "White Rose" around the siblings Sophie and Hans Scholl, whose pamphlets detailing Nazi crimes led to their arrest and execution in 1943.

Four years earlier in Munich, in November 1939, the carpenter Georg Elser planted a time-bomb that almost killed the Nazi leader. He acted alone but most opponents worked in groups. Like Berlin's "Red Orchestra": communists, Catholics, Jews and diplomats who informed Allied forces of Nazi atrocities but were rounded up in 1942 and many executed.

Another Berlin group called itself the "European Union" and campaigned underground for the restoration of democratic rights and a free and socialist Europe.

In one of its many illegal pamphlets, it put its finger on the challenge they all faced: resistance groups were “working without connections . . . many valuable and skilled political people are still isolated”. Like many others, the “European Union” group ended with arrests, interrogations and the executions of many of its members.

For those who survived the Nazis into postwar Germany, however, their resistance achievements and ideals died a second time. A September 1945 demonstration in Berlin to remember the “Victims of Fascism” attracted more than 100,000 marchers. But, immediately thereafter, their achievements were dumped down a memory hole.

Occupying Allied forces seized resistance materials and silenced survivors to cover up how little assistance they were given from abroad. In West Germany, many judges who sent resistance members to their deaths returned to the benches and ensured the “traitor” label stuck to survivors and victims’ families.

Smeared

In East Germany, the Stauffenberg group were discredited as a “clique of counts” or military rats more interested in saving their sinking imperialist ship than establishing a just German state. Members of the Red Orchestra were smeared as Soviet agents in the west and refashioned into ludicrous propaganda figures in the east.

And so most survivors and families of resistance dead experienced the same, shameful fate. Already punished by the Nazis under sippenhaft or "kin liability" laws, most were silenced by postwar authorities, denied pensions and compensation and often refused the return of seized property. Nazi-era rulings against their loved ones were only set aside in 1998; "wartime treason" rulings in 2009.

The Bendler Block exhibition never strays over the line and refashions Nazi Germany as a buzzing hive of resistance it wasn’t. But by retrieving resistance stories, the Berlin exhibition hands a young generation of Germans, many apathetic to the distant war tales, a new and important message.

"You can always do something," noted Der Spiegel this week. "They weren't many but many more than we wanted to believe."