Covering almost 2 million square kilometres, Mexico is a vast country with a more than 3000 kilometre (2000 mile) northern border with the USA. It extends southwards into the isthmus of Central America and has borders there with Guatemala and Belize. Two long mountain ranges, the Sierra Madre Occidental and Sierra Madre Oriental stretch from the USA border to Mexico City. At the northern end of the western range is the area of canyonland and spectacular mountain scenery known as Barranca del Cobre (Copper Canyon). Bigger than Arizona's celebrated Grand Canyon, this area is home to the Tarahumara Indians, an ancient people famed for their long distance running exploits. As much as 1800 metres deep, the interconnecting valleys of the Copper Canyon region presents lots of opportunities for exciting trekking and mountain biking. The 160 kilometre-long 'Silver Trail', for example, is a superb trek that follows an old mining supply route to the Spanish colonial town of Batopilas. From a mountain biker's perspective, some of the best and most varied riding in the world is found here, from slickrock and singletrack to rough jeep roads, with challenging climbs and monster descents.