(AP Photo)
B-24 Air Force on a mission in 1944.
Between 1940 and 1945, Allied forces dropped more than 2.7 million tons of bombs on Europe, producing enough energy to leave a mark at the edge of earth's atmosphere.
About half of that was dropped on Germany, as the Allies attempted to break the back of the Nazi war machine that sent German troops and tanks to the English Channel and the gates of Moscow.
In Germany, the air campaign produced horrors like the February 1945 bombing of Dresden, which killed roughly 25,000 people, many of them civilians and refugees, in the resulting firestorm.
It also took a heavy toll on the forces sent to carry out the devastation. The US 8th Air Force, based in England, took about half of the entire US Army Air Force's casualties - 47,482 out of 115,332, including more than 26,000 killed.
Perhaps its most severe losses came during the bombing of ball-bearing plants around Schweinfurt, in south-central Germany, on October 14, 1943, which author Martin Caidin described as the "most violent, savagely fought, and bloodiest of all the battles in the titanic aerial conflict waged in the high arena over Germany."
Below, you can see how "Black Thursday" unfolded for the Allies.