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 re