In 1939, Hitler's aggression led to the invasion of Poland, which marked the beginning of World War II. In 1940, Hitler's military strategy of Blitzkrieg proved successful in conquering several European countries, including France, Belgium, the Netherlands, and Denmark. He also signed the Tripartite Pact with Italy and Japan, forming the Axis powers.

In 1941, Hitler violated the non-aggression pact with the Soviet Union and launched Operation Barbarossa, which aimed to conquer the USSR. Despite initial successes, the German forces were ultimately defeated by the harsh Russian winter and the Soviet army's resilience. Also, in 1941, the Holocaust began, which aimed to exterminate the Jewish people and other minorities, resulting in the deaths of millions of people.

In 1942, the tide of the war began to turn against Germany, with the Allied forces making significant gains in North Africa and the USSR pushing back against the German army. Hitler became increasingly erratic and paranoid, leading to the dismissal and execution of many high-ranking officers and generals.

In 1944, the Allies launched a massive invasion of Europe, known as D-Day, landing in Normandy, France. Hitler's forces were unable to withstand the Allied onslaught, and Germany began to suffer significant losses on all fronts. In the same year, an unsuccessful assassination attempt was made on Hitler's life.

In 1945, as the war drew to a close, Hitler retreated to his bunker in Berlin. With Soviet troops closing in, Hitler and his wife, Eva Braun, committed suicide on April 30, 1945. A week later, Germany surrendered, ending the war in Europe. Hitler's legacy is one of destruction and genocide, and his actions during World War II continue to have a profound impact on the world today.