"The thing that really got me mad," Ken Burns says in explaining why he felt called to begin "The War," his forthcoming documentary series, "was finding out that a huge number of our high-school graduates think that we fought with the Germans against the Russians in the second world war. It's so unbelievable." Now you or I might have set about trying to fix America's broken educational system, but Burns is a practical man--at least a seven-part, 14½-hour film for PBS is doable. All you need is six years, gigabytes of images, a gift for fund-raising, the right inspiration-perspiration quotient and a high tolerance for bad dreams. "I had a nightmare about Peleliu last night," he says. (That's the vicious and strategically pointless 1944 battle near the Philippines, in part three of the series, which debuts Sept. 23.) "I was trying to get up this little embankment, and the sand kept giving way. That happened all the time when I was making the film--I'd dream we were trying to figure out a problem in the editing room, and all of a sudden I'd be in the battle."