Olmec colossal heads by Matthew Stirling in 1938 spurred the first archaeological investigations of Olmec culture. Seventeen confirmed examples are known from four sites within the Olmec heartland on the Gulf Coast of Mexico. Most colossal heads were sculpted from spherical boulders but two from San Lorenzo Tenochtitlán were re-carved from massive stone thrones. An additional monument, at Takalik Abaj in Guatemala, is a throne that may have been carved from a colossal head. This is the only known example from outside the Olmec heartland. Dating the monuments remains difficult because of the movement of many from their original contexts prior to archaeological
Olmec influences on Mesoamerican cultures earliest evidence of several of the defining traits of Mesoamerican culture is found there, the Olmecs emerge looking less like a mother culture than as a promiscuous father culture spawning offspring generously with many different mothercultures all over mesoamerica. This formulation emphasises the viewpoint that influence from the Olmec heartland merged with many local traditions creating local expressions with both Olmec and non-Olmec roots. it follows from this approach that the type and degree of Olmec influence varies greatly from location to location within Mesoamerica. If Olmec influences flowed out of the heartland in what is generally seen as a