World War II: 75th anniversary

German troops march through occupied Warsaw, Poland, during World War II, circa 1939. September 1 marks the 75th anniversary of the start of World War II. In 1939, Germany invaded Poland. Denmark, Luxembourg, the Netherlands, Norway and Belgium soon came under German control, and when France fell less than a year later, Britain was the only nation left in Western Europe to oppose Adolf Hitler's Third Reich. Click through for key photos from the war.

German troops march through occupied Warsaw, Poland, during World War II, circa 1939. September 1 marks the 75th anniversary of the start of World War II. In 1939, Germany invaded Poland. Denmark, Luxembourg, the Netherlands, Norway and Belgium soon came under German control, and when France fell less than a year later, Britain was the only nation left in Western Europe to oppose Adolf Hitler's Third Reich. Click through for key photos from the war.