As you drive southeast on I-10, the ubiquitous saguaros and mesquite give way to willowy cottonwoods--you're crossing the San Pedro River. After so many miles of highway, the Ghost Town Trail comes as a shock. This unpaved road from Pearce to Tombstone is quite rutted in places and so isolated that you'll be tempted to turn back. Stick with it and you'll pass through remnants of once-booming copper-mining villages.

The Mule Mountain Pass into Bisbee is vertiginous--it's a mile above sea level and the highway twists and turns--but the view is spectacular. The town is nestled in a canyon, with clapboard houses stacked on top of one another; it looks as though one good rain will wash all the buildings away. Now a magnet for artists and retirees, Bisbee was once the heart of copper mining in the area, producing nearly 3 million ounces of gold and 8 billion pounds of copper. At the turn of the century, it was the largest city between St. Louis and San Francisco. See proof at the Mining & Historical Museum. Explore the mine as the miners did--with a hard hat and lantern--on the one-hour underground tour of the Queen Mine.