World War II was a global conflict from 1939 to 1945 involving countries across Europe, Africa, and Asia. It included two main groups: the Allies and the Axis powers. The war affected millions of people around the world.

Major events included the Holocaust, where millions of Jews and others were killed, and large battles across land, sea, and air. In 1945, atomic bombs were dropped on Hiroshima and Nagasaki in Japan. Cities, factories, and transport systems were heavily damaged during the war.

The war ended in 1945 with Germany’s surrender in May and Japan’s surrender in September. It is considered the largest conflict in human history and is studied through documents, photographs, and records.