An early camp, Sachsenhausen was built in 1936 in Oranienburg, on the northern outskirts of Berlin. At first it primarily held political prisoners, but later, other groups that the Nazis identified as dangerous or inferior were also sent there. Intended to be a model for other concentration camps, it was constructed on strict geometrical lines, its stone walls forming an equilateral triangle. Like Dachau, it served as a training center for concentration camp personnel. Between 1936 and its liberation by the Red Army on April 27, 1945, around 200,000 persons were imprisoned at Sachsenhausen, approximately half of whom died or were murdered, many by shots to the back of the neck.
Exhibitions have been placed in several of the extant barracks. At the center of the camp is a large Soviet-era monument. More recently, a memorial to the camp victims was erected near the site of the building where many of the shooting executions took place.