European Day of Remembrance for Victims of Stalinism and Nazismor Black Ribbon Day (European Unionand other countries), and related observances:

Liberation from Fascist Occupation Day(Romania)

European Day of Remembrance for Victims of Stalinism and Nazism, known as Black Ribbon Day, honors those who suffered under totalitarian regimes.
Observed on August 23 in the European Union and beyond, this day commemorates victims of Stalinist and Nazi oppression. It marks the anniversary of the Molotov-Ribbentrop Pact of 1939. In Romania, the same date is also Liberation from Fascist Occupation Day, celebrating the end of Axis control in 1944. Memorial ceremonies, educational events, and public discussions are held to raise awareness of totalitarian crimes and the value of democracy. Black ribbons and wreath-laying at memorials are typical acts of remembrance. The observance encourages reflection on human rights and the importance of safeguarding freedom.
European Day of Remembrance for Victims of Stalinism and Nazism European Union Liberation from Fascist Occupation Day Romania

International Day for the Remembrance of the Slave Trade and its Abolition

This UN observance commemorates the transatlantic slave trade and promotes its abolition.
Declared by UNESCO and recognized by the UN General Assembly, this day falls on August 23 to honor victims of the transatlantic slave trade and reflect on its legacy. It aims to raise awareness of the horrors of slavery, promote education on human rights, and encourage dialogue about historical injustices. Events include symposiums, exhibitions, performances, and educational programs in schools and communities worldwide. The observance fosters solidarity with descendants of enslaved peoples and highlights ongoing efforts for racial justice and equality. It underscores the importance of remembrance in preventing future human rights violations.
International Day for the Remembrance of the Slave Trade and its Abolition