I. Olmec Civilization--the first great civilization of the Americas (that archeologists know about, anyway). 1. Located in the narrow ?waist? of Mexico, recognizable civilization by about 1800 BCE. 2.Lived in towns and cities centered on temple mounds that they built. Created large stone heads with helmets, many over six feet tall, that are vaguely African in appearance and have sparked speculations that African peoples may have made contact with them. 3.Olmec practiced human sacrifice (as did the God of Abraham)