Mexico is one of the top 6 "oldest civilizations".
Most of the South American countries are "new countries" with no more than 200 years of existence. At the moment when the Europeans arrived, in Mexico there were civilized people, living in big cities, with their own traditions, artistic manifestations, architecture, religion, literature and science. Almost all the South American countries (exceptions Peru and Bolivia) were colonized by europeans whom only found empty space when arrived. In Mexico there is a proverb: "Mexicans came from Mexica, Peruvians came from the Inca and Argentinians came from the ships".
Humans have lived in the current Mexican territory from at least 13,000 years. And some evidences suggest ancient Mexicans developed the agriculture in a totally independent and original way 7000 years ago. I hope this helps!
