Recently, YouTube user EmperorTigerstar mapped the changing front lines of WWII as it unfolded across Europe. Now, he's finished the job, compiling a timelapse perspective of the entire war that includes the African, Asian, and Pacific theatres.
Personally, I would have started the clock on July 7th, 1937 — the day the Second Sino-Japanese War began, and a date that some historians consider the true start of World War II. At any rate, things get going in September 1939 with the German invasion of Poland and end with the U.S. bombings of Hiroshima and Nagasaki in August of 1945.
Watching the timelapse, I find the war in the Pacific particularly fascinating — starting with the massive offensive by the Japanese in 1941, followed by the patient but unrelenting island leap-frogging by U.S. forces. Front lines on the water aren't quite like the ones on land.
For a list of key dates in Europe, check out this previous post. Here are the dates to watch for in the Pacific and in Central and East Asia.