On September 1, 1939, Germany invaded Poland, initiating World War II. Britain and France responded by declaring war on Germany on September 3. Within a month, Poland was defeated by a combination of German and Soviet forces.

In the first phase of World War II in Europe, Germany sought to avoid a long war. Germany’s strategy was to defeat its opponents in a series of short campaigns. Germany quickly overran much of Europe and was victorious for more than two years by relying on a new military tactic called the “Blitzkrieg” (lightning war).

Explore the links on this page to learn more about the Holocaust and World War II.