Black Ribbon Day
ブラックリボンデー
スターリニズムとナチズムの被害者記念の欧州の日
Comparison of Nazism and Stalinism
Council of Europe resolution 1481
Days of Remembrance of the Victims of the Holocaust
(United States)
Declaration on Crimes of Communism
Ghost Festival
Platform of European Memory and Conscience
Reconciliation of European Histories Group
World Freedom Day
(United States)
International Holocaust Remembrance Day
https://en.wikipedia.org/wiki/Black_Ribbon_Day