The Mayan Human civilization existed in the southern regions of North America and Central America from the 1st millenium CE through the 9th century.
Kukulkan, a benevolent alien being, periodically visited ancient Earth cilvilizations and influenced their architecture and agricultural development, and was worshipped as a god. Kulkulkan visited the Mayans in the 6th century, and influenced the Egyptian and Aztec cultures as well. Kulkulkan was discovered by the crew of the USS Enterprise (NCC-1701) in 2270. (TAS: "How Sharper Than a Serpent's Tooth")