Nazi eugenics were a set of beliefs and rules that were very important to Nazi Germany during World War II. These beliefs said that the Aryan race was the master race – the best race of all – and all other races were inferior (not as good). There were also many other people who the Nazis believed were "life unworthy of life," like people with disabilities. These ideas about eugenics were at the center of the Nazis' beliefs and eventually helped lead to the Holocaust.