Altona Bloody Sunday: A riot between the Nazi Party paramilitary forces, the SS and SA, and the German Communist Party ensues.

Altona Bloody Sunday is the name given to the events of 17 July 1932 when a recruitment march by the Nazi SA led to violent clashes between the police, the SA and supporters of the Communist Party of Germany (KPD) in Altona, which at the time belonged to the Prussian province of Schleswig-Holstein but is now part of Hamburg. Eighteen people were killed. The national government under Reich Chancellor Franz von Papen and Reich President Paul von Hindenburg used the incident as a rationale to depose the acting government of the Free State of Prussia by means of an emergency decree in what came to be known as the Prussian coup d'état of 20 July 1932.

The Nazi Party, officially the National Socialist German Workers' Party, was a far-right political party in Germany active between 1920 and 1945 that created and supported the ideology of Nazism. Its precursor, the German Workers' Party, existed from 1919 to 1920. The Nazi Party emerged from the extremist German nationalist, racist, and populist Freikorps paramilitary culture, which fought against communist uprisings in post–World War I Germany. The party was created to draw workers away from communism and into völkisch nationalism. Initially, Nazi political strategy focused on anti-big business, anti-bourgeoisie, and anti-capitalism, disingenuously using socialist rhetoric to gain the support of the lower middle class; it was later downplayed to gain the support of business leaders. By the 1930s, the party's main focus shifted to antisemitic and anti-Marxist themes. The party had little popular support until the Great Depression, when worsening living standards and widespread unemployment drove Germans into political extremism.

The Schutzstaffel was a major paramilitary organisation under Adolf Hitler and the Nazi Party in Nazi Germany, and later throughout German-occupied Europe during World War II.