For some destinations, such as Belzec, Sobibor or Treblinka, nearly every Jew who arrived at the camp was exterminated in a matter of hours. However, other camps, including Auschwitz-Birkenau, were designed to also function as slave labor camps for nearby industrial facilities. Upon arrival by train at Auschwitz, the surviving Jews were subjected to a selection. Nazi doctors and guards would inspect each inmate to determine whether he or she might be fit enough to work. The elderly and children were rejected and sent immediately to the gas chambers. Anyone found fit to work was sent on to processing for entry into the slave labor portion of the camp.