Mexico's flag flies in Mexico City. Mexico City is the country's capital, its largest population center and the undisputed political core of Mexico.
As the southernmost portion of North America, Mexico faces a difficult geographic situation. It has a small and limited core territory surrounded by mountains, deserts and jungles that are inherently hard to control and nearly impossible to defend against threats from within or without. The country is funnel-shaped, its high plateau anchored in the mountains and jungles of Central America to the south. The funnel fans and expands northwest toward a 3,200-kilometer-long (2,000-mile-long) desert border with the United States. Bordering the plateau to the east and west are Mexico's two mountain ranges, the Sierra Madre Oriental and the Sierra Madre Occidental. With peaks as high as 5,500 meters (18,000 feet), these mountain ranges are extensive and formidable — indeed, the country can be thought of as a kind of mountain fortress that must secure outlying territories that serve as approaches to its core.
