A country of contrasts
Mexico shares its borders with three countries: its northern border with the United States is 3,152 km, of which 2,493 correspond to the course of the Bravo River, or Río Grande, from Ciudad Juárez to the Gulf of Mexico. The southern border, bordered by Belize and Guatemala, is 1,149 km long, of which 85 km is the Suchiate River and 300 km is the Chixoy and Usumacinta Rivers. Mexico is surrounded by the Pacific Ocean and the Gulf of Mexico to the west and the Caribbean Sea and the Gulf of California to the east. Thanks to this particular geographical situation, the country has 9,219 km of coastline (6,608 km on the Pacific side and 2,611 km on the Atlantic side). Its maritime borders are therefore more important than its land borders. In Mexico, the traveller is confronted with a great variety of landscapes, between the green plains of the coasts; the dry and rocky north where the visitor can admire the breathtaking gorges of the Barrancas del Cobre and the lunar landscapes of the Pinacate reserve, in the Sonora desert; the lush and humid south, with its tropical forests that are home to thousands of species of animals; and the temperate or cold centre, depending on the altitude, which gives the visitor a glimpse of the country's highest peaks.
A rugged terrain
Just 32% of Mexico's land area is below 500 m, 37% between 1,000 and 2,000 m, and 42% above 2,000 m. Three major mountain ranges, the Sierra Madre Oriental (home to Pico de Orizaba, the country's highest point), the Sierra Madre Occidental (home to Lake Chapala, Mexico's largest lake), and the Sierra Madre del Sur divide the country parallel to the two oceans. This mountainous terrain is made up of volcanoes, some of which are still active. Rivers flow through these mountains and feed the forests that cover 33% of Mexico's territory, along the coasts and in the south, on the Yucatán Peninsula. These mountain ranges converge in the center of the country and surround the Mexican plateau, which covers a huge area of 601,882 square kilometers and is home to Mexico City, one of the highest capitals in the world. Built on the bed of an ancient salt lake, Mexico City is sinking inexorably into the ground at a rate of 50 cm per year. Its irreversible subsidence is being precipitated by the intensive pumping of groundwater to supply the city with drinking water.
A seismic and volcanic land
Mexico is part of the Pacific Ring of Fire, a vast area around the Pacific Ocean where three quarters of the world's volcanoes are concentrated and where the vast majority of earthquakes occur. The country belongs to the North American tectonic plate, under which the Cocos oceanic plate sinks, forming a subduction zone. When these pieces of the earth's crust move, grind, rub and overlap, earthquakes occur. The meeting of the tectonic plates also leads to volcanic eruptions, which can be devastating. Mexico is home to 44 volcanoes, most of which are over 4,500 m high. Nevado de Toluca, located southwest of Mexico City, rises to 4,583 m. Iztaccíhuatl ("the sleeping woman"), in the southeast of the Distrito Federal, reaches 5,286 m. The most famous, the Popocatépetl, the smoking mountain, located near the previous one, culminates at 5 452 m. Finally, the highest volcano of the country, the Pico de Orizaba, halfway between Puebla and Veracruz, does not pass unnoticed with its 5 636 m of altitude. Volcanic phenomena are a constant threat to the country, as are earthquakes. In 1943, a new volcano was born in the state of Michoacán: Paricutín. After nearly ten years of pouring lava on the surrounding villages, it left only a church steeple emerging from a black ocean. Paricutin is one of the most recent volcanoes on the planet. If lava flows are the most feared element of volcanic phenomena, it also happens that their awakening causes earthquakes. This is what happened in 1973 in the state of Colima, when Nevado de Colima and Volcán de Fuego erupted.
Natural wonders of Mexico
Mexico is a fascinating country, overflowing with geological curiosities. The cenotes, well known to the tourists who invade the Yucatán Peninsula every year to bathe, are one of the country's most emblematic geological singularities. These natural wells of fresh water formed by the effect of erosion can reach several meters in depth. They shelter an entire ecosystem and offer access to an underground aquatic network that leads to the ocean. Cenotes are found in only a few places on the planet, and the Yucatán Peninsula is the world's most densely populated region: some 5,000 cenotes have been mapped, but satellite images indicate that the peninsula may be home to nearly 10,000. The Yucatán Peninsula is also home to the Chicxulub crater, which was formed about 66 million years ago when a 10-kilometre diameter asteroid collided with the Earth. This impact is likely to have been the cause of a mass extinction event and the disappearance of the dinosaurs. Another geological curiosity, this time in the state of Chihuahua, in northern Mexico, is the selenite crystals of the Naica mine, considered one of the most beautiful underground wonders on the planet. Located 1,000 meters below ground, this lead, silver and zinc mine contains gypsum crystals that can measure up to 11 meters! The temperature (up to 58°C) and humidity (up to 99%) conditions made the formation of these crystals possible. Finally, the town of Aquismón, in the state of San Luis Potosí in central Mexico, is home to the natural cavity of Sótano de las Golondrinas, or Swallow Chasm. This place is well known to base jumpers, who like to throw themselves from its highest point to descend its 350 meters of depth.
