Guadalajara rests on a mile-high plain of the Sierra Madre del Occidente, surrounded on three sides by rugged hills and on the fourth by the spectacular Barranca de Oblatos (Oblatos Canyon). Mexico's second-largest city has a population of 4 million and is the capital of the western state of Jalisco. There's a mishmash of terrain here: pine-forest mountain ranges, semideserts, and coastal mangrove swamps.