World War II saw modern industrial nations, which represented the best of the Enlightenment and the Scientific Revolution, descend into once unimaginable cruelty. And what makes World War II such a historical watershed is that in its wake, all of us, in the West or otherwise, were forced to question whether Western dominance of this planet could or should be considered progress. Thanks for watching. I'll see you next week. Crash Course is produced and directed by Stan Muller. Our script supervisor is Meredith Danko. Our associate producer is Danica Johnson.