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
Mayan languages and a special word class of "positionals" which is typical of all Mayan languages. During the pre-Columbian era of Mesoamerican history, some Mayan languages were written in the logo-syllabic Maya script. Its use was particularly widespread during the Classic period of Maya civilization (c. 250–900). The surviving corpus of over 10,000 known individual Maya inscriptions on buildings, monuments, pottery and bark-paper codices, combined with the rich postcolonial literature in Mayan languages written in the Latin script, provides a basis for the modern understanding of pre-Columbian history unparalleled in the Americas. Mayan languages are the descendants of a proto-language called Proto-Mayan