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 colossal heads where they are associated with the potbelly style of sculpture. Although some arguments have been made that they are pre-Olmec, these latter monuments are generally believed to be influenced by the Olmec style of sculpture. The ten colossal heads from San Lorenzo originally formed two roughly parallel lines running north-south across the site. Although some were recovered from ravines, they were found close to their original placements and had been buried by local erosion. These heads, together with a number of monumental stone thrones, probably formed a processional route across the site, powerfully displaying its dynastic history. Two of the