Firehole Canyon Drive
The 2-mile narrow asphalt road twists through a deep canyon of curving lava-rock formations and passes the 40-foot Firehole Falls, which are most scenic in the morning when you're not looking into the afternoon sun. In summer look for a sign marking a pull-out and swimming hole. This is the only place where you can safely and legally swim in the thermally heated waters. Look for osprey and other raptors.