Not all the European Jews who were deported to Poland were murdered immediately. There was a selection process in Auschwitz to determine who would live and work and who would be killed. Thousands of prisoners were forced into slave labour. In 1944, when the Soviet army advanced towards Berlin and started to get close to the nazi concentration and extermination camps, the surviving prisoners were forced to march to the west. During these death marches, thousands of prisoners were shot dead because they were too sick or weak to walk; others died of starvation, sickness, and extremely cold weather. During the evacuation of Auschwitz at the end of 1944 and beginning of 1945, tens of thousands of prisoners were marched westward; around 15,000 were murdered or died along the way. Similar evacuations were also organised from other camps, including Dachau, Ravensbrück, Mauthausen, and Neuengamme, and from cities such as Budapest. It is estimated that during the last two months of the war 250,000 victims died as a result of these death marches.