Operation Reinhard was a secret Nazi plan during World War II aimed at the systematic extermination of the Jewish population in occupied Poland. It was named after Reinhard Heydrich, a high-ranking Nazi official. The operation began in 1942 and involved the establishment of extermination camps, including Treblinka, Sobibor, and Belzec. The operation resulted in the deaths of approximately 1.5 million Jews and was a key part of the broader Holocaust. It utilized mass shootings and gas chambers to carry out the killings, reflecting the extreme measures taken by the Nazis to implement their genocidal policies.