Aztec
The Aztec Native American Human civilization existed in the southern regions of North America (an area that later included the nation-state of Mexico) on Earth from the 14th to the 16th century. 

Kukulkan, a benevolent alien being, visited ancient Earth civilizations and influenced their architecture and agricultural development. Kukulkan was worshiped as a god and knowledge of his visit was passed on to the Aztecs, who still remembered him in their culture. Kukulkan was discovered by the crew of the  in 2270. ()

See also 
Sangre del Mumiaazteca

External link 
 

fr:Aztèque
de:Azteke
Earth groups