Chattanooga has charisma to spare. With world-class rock climbing, hiking, cycling and water-sports opportunities, it's one of the South's best cities for outdoorsy types. It's gorgeous, too: just check out those views from the Bluff View Art District! It's also remarkably eco-forward, with free electric buses, miles of well-used waterfront trails, and pedestrian bridges crossing the Tennessee River. All this makes it hard to credit its reputation in the 1960s as America's dirtiest city.