Extermination camps (death camps) were built by Nazi Germany during World War II. The goal of the death camps was to kill millions of people as quickly as possible. At the death camps, people were murdered mostly by being given poison gas in gas chambers. However, the Nazis also killed many people in other ways at the death camps. They killed some in mass executions (for example, by shooting many people at once). They killed others through "extermination through labor." This was by making prisoners do very hard forced labor without giving them the food, medical care, or other basic things they needed to survive. Many other people died at the death camps from starvation, illness, and freezing to death.