The Vietnam War by Ken Burns, right up there with WW2 in HD as the greatest war documentary series I've seen.
Just can't recommend it enough, you'll rage, cry, feel bouts of melancholy and never trust a government again.
Just to think, within my parents lifetime in America, a young man could be drafted and forced to go to war in Vietnam where as now they go voluntarily to backpack and drink cheap beer. The world changed fast and it was down to the will of the people.