In early April 1945, as US troops were advancing towards the Harz, the SS decided to evacuate most of the Mittelbau camps. In great haste and with considerable brutality, the inmates were forced to board box cars. Several trains, each with thousands of prisoners, left the area through 6 April for Bergen-Belsen, Sachsenhausen and Ravensbrück. Others were forced to walk through the Harz hills towards the northeast. Those unable to keep up with these death marches were summarily shot by the guards.