According to testimony given at the Nuremberg IMT, approximately 150 Dachau inmates were forced to participate in medical experiments conducted by Dr. Sigmund Rascher for the German Air Force, and about half of them died as a result. The subjects for these experiments were allegedly German "professional criminals" and Soviet POWs who were Communist Commissars, sentenced to be executed on the orders of Adolf Hitler. One Jew, who had been condemned to death for breaking the law against race mixing, was used in these experiments.
Anti-Jewish measures were introduced in Slovakia, which would later deport its Jews to German concentration and extermination camps. Bulgaria introduced anti-Jewish measures in 1940 and 1941, including the requirement to wear a yellow star, the banning of mixed marriages, and the loss of property. Bulgaria annexed Thrace and Macedonia, and in February 1943 agreed to deport 20,000 Jews to Treblinka; all 11,000 Jews from the annexed territories were sent to their deaths, and plans were made to deport an additional 6,000–8,000 Bulgarian Jews from Sofia to meet the quota. When the plans became public, the Orthodox Church and many Bulgarians protested, and King Boris III canceled the deportation of Jews native to Bulgaria. Instead, they were expelled to the interior pending further decision. Although Hungary expelled Jews who were not citizens from its newly annexed lands in 1941, it did not deport most of its Jews until the German invasion of Hungary in March 1944. Between 15 May and 9 July 1944, 440,000 Hungarian Jews were deported to Auschwitz. In late 1944 in Budapest, nearly 80,000 Jews were killed by the Hungarian Arrow Cross battalions.
The camp was liberated on April 15, 1945, by the British 11th Armoured Division. The soldiers discovered approximately 60,000 prisoners inside, most of them half-starved and seriously ill, and another 13,000 corpses, including those of Anne and Margot Frank, lying around the camp unburied. The horrors of the camp, documented on film and in pictures, made the name "Belsen" emblematic of Nazi crimes in general for public opinion in many countries in the immediate post-1945 period. Today, there is a memorial with an exhibition hall at the site.