The Holocaust: Nazi forces, aided by Ukrainian collaborators, began a massacre of Jews in a ravine in Kyiv, killing more than 30,000 civilians in two days and thousands more in the following months.

The Holocaust, known in Hebrew as the Shoah, was the genocide of European Jews during World War II. From 1941 to 1945, Nazi Germany and its collaborators systematically murdered some six million Jews across German-occupied Europe, around two-thirds of Europe's Jewish population. The murders were committed primarily through mass shootings across Eastern Europe and poison gas chambers in extermination camps, chiefly Auschwitz-Birkenau, Treblinka, Belzec, Sobibor, and Chełmno in occupied Poland. Separate Nazi persecutions killed millions of other non-Jewish civilians and prisoners of war (POWs); the term Holocaust is sometimes used to include the murder and persecution of non-Jewish groups.

Ukrainian collaboration with Nazi Germany took place during the occupation of Poland and the Ukrainian SSR, USSR, by Nazi Germany during the Second World War.

Babi Yar or Babyn Yar is a ravine in the Ukrainian capital Kyiv and a site of massacres carried out by Nazi Germany's forces during its campaign against the Soviet Union in World War II. The first and best documented of the massacres took place on 29–30 September 1941, in which some 33,771 Jews were murdered. Other victims of massacres at the site included Soviet prisoners of war, communists and Romani people. It is estimated that a total of between 100,000 and 150,000 people were murdered at Babi Yar during the German occupation.