The Olmecs were the first major civilization known of in Mexico. Their time period was 1500 BC to 400 BC. One of the most significant things about these people are their amazing and striking art work.
They were known for their colossal heads that looked helmeted in size and shape.
There are some theories floating around about the exceptional Olmecs that they were perhaps an African Tribe. From this site; "The Olmecs used an African practice that is very common in Africa and to some extent in Melanesia. That practice is body scarification and specifically facial scarification as practiced in West Africa. Many of the facial scars seen on the Olmec terracotta faces, such as "dot" keloids and "lined" patterns are identical to Africans such as the Dinka of Sudan and the Yoruba and others of West Africa. (Dinka scarification can be found in old copies of National Geographic. Olmec scarification can be found in the text by "Alexander Von Wuthenau, Unexpected Faces in Ancient America." African hairstyles such as cornroes are found on many of the Olmec terracotta found in Mexico. Both kinky hair carved into one of the collosal stone heads of basalt, as well as the cornroed style wearing tassels (see African Presence in Early America, by Ivan Van Sertima; Transaction Publishers), have been found. The "cornrow" factor clearly shows that these Blacks who were in Mexico in prehistoric times most likely came from the West Africa/South Sahara region, rather than Melanesia. It is in West Africa that cornroes are very common and have been since prehistoric times."
Another theory is that the Olmecs had ancient alien influences-