On April 29, 1945, the U.S. Seventh Army’s 45th Infantry Division liberates Dachau, the first concentration camp established by Germany’s Nazi regime. A major Dachau subcamp was liberated the same day by the 42nd Rainbow Division.

Established five weeks after Adolf Hitler took power as German chancellor in 1933, Dachau was situated on the outskirts of the town of Dachau, about 10 miles northwest of Munich. During its first year, the camp held about 5,000 political prisoners, consisting primarily of German communists, Social Democrats, and other political opponents of the Nazi regime. During the next few years, the number of prisoners grew dramatically, and other groups were interned at Dachau, including Jehovah’s Witnesses, Roma peoples, homosexuals and repeat criminals. Beginning in 1938, Jews began to comprise a major portion of camp internees.

Prisoners at Dachau were used as forced laborers, initially in the construction and expansion of the camp and later for German armaments production. The camp served as the training center for SS concentration camp guards and was a model for other Nazi concentration camps. Dachau was also the first Nazi camp to use prisoners as human guinea pigs in medical experiments. At Dachau, Nazi scientists tested the effects of freezing and changes to atmospheric pressure on inmates, infected them with malaria and tuberculosis and treated them with experimental drugs, and forced them to test methods of making seawater potable and of halting excessive bleeding. Hundreds of prisoners died or were crippled as a result of these experiments.

Thousands of inmates died or were executed at Dachau, and thousands more were transferred to a Nazi extermination center near Linz, Austria, when they became too sick or weak to work. In 1944, to increase war production, the main camp was supplemented by dozens of satellite camps established near armaments factories in southern Germany and Austria. These camps were administered by the main camp and collectively called Dachau.

With the advance of Allied forces against Germany in April 1945, the Germans transferred prisoners from concentration camps near the front to Dachau, leading to a general deterioration of conditions and typhus epidemics. On April 27, 1945, approximately 7,000 prisoners, mostly Jews, were forced to begin a death march from Dachau to Tegernsee, far to the south. The next day, many of the SS guards abandoned the camp. On April 29, the Dachau main camp was liberated by units of the 45th Infantry after a brief battle with the camp’s remaining guards.

As they neared the camp, the Americans found more than 30 railroad cars filled with bodies in various states of decomposition. Inside the camp there were more bodies and 30,000 survivors, most severely emaciated. Some of the American troops who liberated Dachau were so appalled by conditions at the camp that they machine-gunned at least two groups of captured German guards. It is officially reported that 30 SS guards were killed in this fashion, but conspiracy theorists have alleged that more than 10 times that number were executed by the American liberators. The German citizens of the town of Dachau were later forced to bury the 9,000 dead inmates found at the camp.

In the course of Dachau’s history, at least 160,000 prisoners passed through the main camp, and 90,000 through the subcamps. Incomplete records indicate that at least 32,000 of the inmates perished at Dachau and its subcamps, but countless more were shipped to extermination camps elsewhere.