Before Mexico City Urbanized

Mexico city was once the capital of the Aztec nation which the region was then known as Tenochtitlan, 

"The Place of the Mexicas".

 In the 16th century, Spaniards invaded the Aztec territory to defeat and conquer their land and soon the region grew in population and size. The Spaniards sought to rid the city of all Aztec remnants by building the city in their culture of Spain. However, what many forget about the region in which Mexico City lies is that the Aztecs chose the area because of its defensive capability. 

You can see that the Aztec capital is surrounded by mountains, dry land and a large lake called, Lake Texcoco in the image above. The region has a subtropical highland climate because it has a high elevation and surrounded by mountains. This means that the lower areas receive less rainfall than the higher areas in the south and the west is usually drier and warmer. Since the region is surrounded by mountains this causes air to be trapped within  the region (this will be further explained below).

Lake Texcoco has a system of interconnect saline and freshwater lakes in which the Aztecs used for their advantage by creating dikes to separate the different water types so that they could use fresh water to raise crops while preventing floods. These dikes, however, were destroyed in the conquest of the Aztec nation and now these what's left of the lake can be seen outside of downtown Mexico City.

Mexico City Today