There’s a sobering interactive called The Invasion of America: How the United States took over an eighth of the world that shows the steady, seemingly inexorable westward advance of the U.S. border. Click the arrow at bottom left for the overall animation; Highlight by Nation at the top. It’s worth remembering that every step of that advance was complicated, with no clear “whites v. reds” dynamic most of the time. Just as the “ground” beneath modern cities is just the top layer of 50 feet of previous top layers of previous cities, societies, and civilizations that have fallen, so the United States as we know it today is just the top layer of a long history of peoples. It makes you wonder what layers will cover our own in the future.