A number of people and events influenced the course and outcome of World War II. This helpful timeline of World War II (WWII) maps out those key figures and actions in the years surrounding the war.Examining the beginnings of World War IIOfficially, World War II began when Nazi Germany invaded Poland in September 1939 and the French and English declared war against Germany as a result of that invasion.

For a brief rundown of World War II, check out the following chart, which highlights critical political events, leaders, and military action in the years preceding, during, and following the war: Click here to download and print this timeline.

Relations between The Democratic People's Republic of Korea (North Korea) and The Republic of Korea (South Korea) haven't always been as strained and controversial as they are today. In fact, the division of the two countries is a relatively recent phenomenon. Before World War II, Korea was united in language, culture, and politics for over a millennium.

Officially, World War II began when Nazi Germany invaded Poland in September 1939 and the French and English declared war against Germany as a result of that invasion. But the war's beginnings came long before this invasion. World War II was the product of a lot of things coming together in just the wrong way at just the wrong time.

The admirals in both the American and Japanese navies had grown up believing that the decisive naval action in the Pacific would be one straight out of the age of sail — two big battle fleets fighting within sight of each other, with the heavily armored and armed battleship providing the decisive edge. For nearly a generation, the war plans of both nations had envisaged such an engagement — that's why both Japan and the United States built big battleships and why the disarmament efforts of the 1920s focused on reducing the size and number of battleships in the world's fleets.

The years after World War II weren't peaceful. But they didn't erupt into World War III either (cross your fingers). For much of the time after World War II, the major world powers were preoccupied with a game of nuclear standoff. The major powers, by the way, turned out to be the United States and the Soviet Union.

Japan's ambassadors delivered the first part of a final Japanese diplomatic note to U.S. Secretary of State Cordell Hull on December 6, 1941. On the morning of December 7, the final portion of the note arrived from Tokyo to the Japanese ambassadors. The note broke diplomatic relations with the U.S. and provided instructions to destroy the code machines in the Japanese embassy.

Even before World War II began, scientists fleeing from Nazi Germany had warned U.S. officials the Germans were working on developing a huge new bomb that would be triggered through an atomic reaction. The U.S. government then began pouring what would amount to more than $2 billion into what would be called the “Manhattan Project.