How was the Holocaust and World War II related?

It culminated in the construction of extermination camps -- government facilities whose entire purpose was the systematic murder and disposal of massive numbers of people. In 1945, as advancing Allied troops began discovering these camps, they found the results of these policies: hundreds of thousands of starving and sick prisoners locked in with thousands of dead bodies. They encountered evidence of gas chambers and high-volume crematoriums, as well as thousands of mass graves, documentation of awful medical experimentation, and much more. The Nazis killed more than 10 million people in this manner, including 6 million Jews.