Adolf Hitler led the Nazis during World War II as the Chancellor of Germany from 1933 until his death in 1945. His aggressive expansionist policies and totalitarian regime were central to the conflict, which resulted in catastrophic global consequences. Under Hitler's leadership, the Nazis initiated World War II by invading Poland in 1939, and implemented horrific policies that led to the Holocaust, systematically exterminating millions of Jews and other groups. His ambitions for German dominance ultimately led to his downfall and the devastation of Europe, reshaping the world order in the aftermath of the war.