When people talk about the Copper Canyon (la Barranca del Cobre), they are referring to a section of the Sierra Madre of northwestern Mexico known as the Sierra Tarahumara (after the indigenous people who live there). To appreciate the Copper Canyon, it's best not to think of it as a variation on the Grand Canyon. Geologically they are not alike. This area is much newer, having formed through violent volcanic uplifting. The topography is more varied, creating the existence of microclimes in the Sierra Tarahumara that provide a far greater range of flora and fauna. And the local Indian cultures, especially the Tarahumara, are nothing like the Native Americans that live near the Grand Canyon.

How one experiences the canyons is very different. Winding through the Copper Canyon is one of the most remarkable railways in the world: the famed Chihuahua al PacĂ­fico (Chihuahua to the Pacific) railway. Acclaimed as an engineering marvel, the 624km (387-mile) railroad has 39 bridges -- the highest is more than 300m (984 ft.) above the Chinipas River, and the longest is about .5km (1/3 mile) long -- and 86 tunnels, including one that stretches more than 1.5km (1 mile) long. It climbs from Los Mochis, at sea level, up nearly 2,425m (7,954 ft.) through some of Mexico's most magnificent scenery -- thick pine forests, jagged peaks, and shadowy canyons -- before descending to the city of Chihuahua.