On the second Sunday in January, activists and admirers visit the gravesite of Rosa Luxemburg in Berlin, a tradition begun after the Nazi era in the former East Germany.
Jailed for her opposition to the First World War, Luxemburg had been released after the signing of the armistice.
A Social Democratic (SPD) government had taken charge in postwar Germany, and it was busy quelling a Spartacus League workers' uprising in Berlin. Luxemburg (formerly with Spartacus League) supported the uprising after it took place, but did not favour it beforehand.
Rosa Luxemburg was by now a founder of the German Communist Party; she called for a postwar revolution to rid Germany of capitalist imperialism.