El Paso's sister city, Ciudad Juárez, is the fourth-largest city in Mexico with approximately three million residents. Together, the cities form the largest binational population in the world. Juárez is a regional manufacturing center, due to cheap, abundant labor, and companies such as General Motors and Sony have facilities in the city. Juárez is seedy in the same way as other border cities such as Nogales and Tijuana are, but it is more of a real Mexican city, not one that is built on tourism alone. Juárez's history and authenticity, in my opinion, make it an interesting stop for an afternoon, or even an entire day. (If you're headed specifically to Marfa or Big Bend, however, it probably isn't worth the diversion.)

Like El Paso, Juárez's modern history begins with Spanish conquistador Juan de Oñate crossing the Rio Grande in 1581. The oldest structure on the border, La Misíon de Nuestra Señora Guadalupe (Our Lady of Guadalupe Mission), was completed in 1668 and remains in remarkably good condition today. The city played important roles in the Mexican-American War and the Mexican Revolution, and was once frequented by Pancho Villa.

Today, the city's booming manufacturing industry is complemented by tourism, with many visitors crossing the border to take in the colorful outdoor markets, historic missions, and lively nightlife. Tourists often drive across the five bridges scattered around El Paso, park in downtown El Paso and walk across, or else take a taxi or a trolley tour. The bridges, aside from the "Free Bridge" (or Cordova Bridge) south of I-10 via U.S. 54, all charge nominal tolls, even to pedestrians, of 25¢ to $2. The most convenient points of entry are the two downtown bridges, at Stanton Street and Santa Fe Street. U.S. currency is welcome practically everywhere in Juárez.

The Copper Canyon

El Paso is often a jumping-off point for trips to the Copper Canyon in northwestern Mexico. If you are interested in seeing a rugged and beautiful land; if you're interested in taking one of the most remarkable train trips in the world; if you're interested in hiking or riding horseback through remote areas to see an astonishing variety of flora and fauna; or if you're curious about a land still populated by indigenous people living pretty much the way they have for centuries, the Copper Canyon is the place to go.

Most often, when people say "Copper Canyon," they are referring to a section of the Sierra Madre known commonly in Mexico as the Sierra Tarahumara (after the Indians who live there). The area was formed through violent volcanic uplifting, followed by a slow, quiet process of erosion that carved a vast network of canyons into the soft volcanic stone.

Crossing the Sierra Tarahumara is the famed Chihuahua al Pacífico (Chihuahua to the Pacific) railway. Acclaimed as an engineering marvel, the 390-mile railroad has 39 bridges (the highest is more than 1,000 ft. above the Chinipas River) and 86 tunnels. It climbs from Los Mochis, at sea level, up nearly 8,000 feet through some of Mexico's most magnificent scenery -- thick pine forests, jagged peaks, and shadowy canyons -- before descending again to its destination, the city of Chihuahua.

It's easier than ever to get to the region, but it's trickier than ever to travel through it on your own -- hotel rooms can be hard to come by, and there have been numerous changes in the operation of the Copper Canyon train. Consequently, this is not the place to do casual, follow-your-nose traveling. A number of tour operators and packagers book trips to the Copper Canyon, such as Sun Travel (tel. 800/874-4042). The easiest thing is to contract with an agency that will plan your trip from El Paso. Or you can take a bus to Chihuahua and contact a travel agency there that will book a trip into the canyon. This would be the cheapest and most flexible way to do it. I recommend Turismo al Mar (tel. 877/228-1288; www.copper-canyon.net).

Another option is to go with a custom tour operator; travel through these companies generally allows you more time in the canyon and a better experience. The best of the bunch is Canyon Travel (tel. 800/843-1060; www.canyontravel.com), which is pretty much in a class by itself. It has lined up some beautiful small lodges in the canyons and staffed them with talented local guides. Another operator that provides good service is the El Paso-based Native Trails (tel. 800/884-3107; www.nativetrails.com).

For more information on traveling in the Copper Canyon, pick up a copy of Frommer's Mexico or check out www.frommers.com/destinations/thecoppercanyon.

Note: This information was accurate when it was published, but can change without notice. Please be sure to confirm all rates and details directly with the companies in question before planning your trip.