quality:corruption
The Olmec colossal heads are stone representations of human heads sculpted from large basalt boulders. They range in height from 1.17 to 3.4 metres (3.8 to 11.2 ft). The heads date from at least 900 BC and are a distinctive feature of the Olmec civilization of ancient Mesoamerica. All portray mature individuals with fleshy cheeks, flat noses, and slightly-crossed eyes; their physical characteristics correspond to a type that is still common among the inhabitants of Tabasco and Veracruz. The backs of the monuments often are flat. The boulders were brought from the Sierra de Los Tuxtlas mountains of Veracruz. Given that the extremely large slabs of stone used in their production were transported over large distances (over 150 kilometres (93 mi)), requiring a great deal of human effort and resources, it is thought that the monuments represent portraits of powerful individual Olmec rulers. Each of the known examples has a distinctive headdress. The heads were variously arranged in lines or groups at major Olmec centres, but the method and logistics used to transport the stone to these sites remain unclear. They all display distinctive headgear and one theory is that these were worn as protective helmets, maybe worn for war or to take part in a ceremonial Mesoamerican ballgame.

The discovery of the first colossal head at Tres Zapotes in 1862 by José María Melgar y Serrano was not well documented nor reported outside of Mexico. The excavation of the same colossal head 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 investigation. Most have been dated to the Early Preclassic period (1500–1000 BC) with some to the Middle Preclassic (1000–400 BC) period. The smallest weigh 6 tons, while the largest is variously estimated to weigh 40 to 50 tons, although it was abandoned and left uncompleted close to the source of its stone.