As the sun rose on Nov. 14, 1965, a clear, hot Sunday, four U.S. Army helicopters flew, as unobtrusively as such machines can, across the rugged Ia Drang Valley in South Vietnam's Central Highlands. Below them was a wild and desolate place that in normal times offered a living only to elephants, tigers and a few Montagnard tribesmen. Lt. Col. Harold G. Moore scanned the terrain intently, scribbling notes and marking his maps. He was about to lead the U.S. 7th Cavalry on its most audacious charge since Lt. Col. George A. Custer led his troopers to the Little Bighorn...