What date is the European Day of Remembrance for Victims of Stalinism and Nazism?

European Day of Remembrance for Victims of Stalinism and Nazism, also known as Black Ribbon Day in some countries, is an international day of remembrance for victims of totalitarian regimes, specifically Stalinism, communism, Nazism and fascism. It is observed on 23 August and symbolizes the rejection of "extremism, intolerance and oppression". It is one of the official remembrance days of the European Union. Under the name Black Ribbon Day it is also an official remembrance day of Canada and the United States, among other countries.

23 August was chosen to coincide with the date of the signing of the Molotov–Ribbentrop Pact, a 1939 non-aggression pact between the USSR and Nazi Germany which contained a protocol dividing Romania, Poland, Lithuania, Latvia, Estonia, and Finland into designated German and Soviet spheres of influence. The treaty was described by the European Parliament's president Jerzy Buzek in 2010 as "the collusion of the two worst forms of totalitarianism in the history of humanity." The remembrance day originated in protests held in western cities against Soviet crimes and occupation in the 1980s, initiated by Canadian refugees from countries occupied by the Soviet Union.