The Reichstag Bloodbath of January 13, 1920, the bloodiest demonstration in German history.

The Reichstag Bloodbath occurred on 13 January 1920 in front of the Reichstag building in Berlin during negotiation by the Weimar National Assembly on the Works Councils Act. The number of people killed and injured is controversial, but it is certainly the bloodiest demonstration in German history. The event was a historic event that was overshadowed two months later by the Kapp Putsch but remained in Berlin's labour movement and security forces' collective memory.

January 13 is the 13th day of the year in the Gregorian calendar; 352 days remain until the end of the year.