U.S. Army Gen. Douglas MacArthur, bottom right, prepares to accept Japan's unconditional surrender on September 2, 1945.

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World War II came to an end 68 years ago when Japan formally surrendered

Millions of people, both military and civilian, were killed during six years of conflict

Approximately 6 million people died in Nazi concentration camps

CNN  — 

When Germany invaded Poland on September 1, 1939, it was the second time the world went to war. With the Japanese surrender on September 2, 1945, World War II was over.

Here is some background information about the end of World War II, by the numbers.

3 -- Nations leading the Axis Powers at the start of World War II: Germany, Italy and Japan.

4 -- Nations leading the Allied Powers: Great Britain, the United States, the USSR (Soviet Union) and China.

September 1, 1939 – Germany invades Poland

December 7, 1941 – Japan bombs Pearl Harbor, Hawaii and Manila, Philippines.

September 3, 1943 Day Italy signs an unconditional surrender with the Allied Powers in Sicily.

June 6, 1944 – D-Day, the Allied invasion of Europe

50 feet – Depth underground of the bunker in which Adolf Hitler and partner Eva Braun committed suicide below the Chancellery in Berlin on April 30, 1945.

May 8, 1945 -- V-E Day (Victory in Europe), after Gen. Alfred Jodl of the German High Command signs the unconditional surrender of all German forces.

2 -- Atomic bombs dropped on Japan in August 1945.

August 14, 1945 -- V-J Day (Victory in Japan), when the Japanese accepted the terms of the Potsdam Declaration and unconditionally surrendered.

September 2, 1945 - Day the Japanese delegation formally signs the instrument of surrender on board the USS Missouri, marking the official ending of World War II.

2,194 -- Days between the German invasion of Poland on September 1, 1939, through September 2, 1945, when Japan signs the unconditional surrender.

4 -- Flags flown on the USS Missouri – those of United States, Great Britain, USSR and China – when the surrender papers are signed.

255 -- Allied ships in Tokyo Bay for the surrender ceremony.

18 minutes – Time it took for representatives of Japan, the United States, China, Great Britain, the USSR, Australia, Canada, France, The Netherlands and New Zealand to each sign two copies of the Instrument of Surrender, from 9:04 a.m. to 9:22 a.m.

16 million -- Americans who serve during World War II.

73,661 -- The number, as of May 2013, Americans classified as missing in action in World War II.

26.6 million -- Estimated number of casualties, military and civilian, suffered by the USSR.

10 million-20 million – Estimated number of casualties, military and civilian, suffered by China from the fall of Manchuria in 1931 through the end of World War II.

6 million -- Approximate number of people killed in Nazi concentration camps.