Valley of Mexico

The Valley of Mexico or the Basin of Mexico (Spanish: Valle de México ) is located at about 2,000 meters, septic plateau in central Mexico. It houses with Mexico City, the capital of the country and with the Zona Metropolitana del Valle de México one of the largest metropolitan areas in the world.

The plateau is bounded on the west, south and east by mountains, including the famous twin volcanoes Popocatepetl and Iztaccihuatl. To the west of the Valley of Mexico is the valley of Toluca, east of it the Valley of Puebla, in the south of the system of the Río Balsas. To the north the climate is dry, the vegetation is steppe.

In the middle of the valley of the endorheic Lake Texcoco, which was fed by springs from the south and therefore the north was always salty lay. On an island in the middle of the lake lay the city of Tenochtitlán, on its banks many other important cities in the pre-Columbian time as Texcoco, Tlacopan or the time-honored Colhuacan. The lake was almost completely dried up in the wake of the expansion of Mexico City.

The unity of the valley on three sides, frequent temperature inversions and, associated with poor air movement near the ground also explain why Mexico City has to constantly fight with smog.