The first evidence of deforming skulls was found in the northern Mexican state of Sonora when residents were digging an irrigation canal in 1999.
Many of the burials at the site were healthy children, suggesting the process of cranial deformation may have been inept and dangerous.
Some of the skeletons were found with various pieces of jewelry.
One of the burials included a turtle shell on the individual's chest.
An up-close image of the turtle shell in the burial.
It is common for people to wonder if skeletons such as these are alien rather than human.
The pre-Hispanic cemetery is located 300 metres from the village of Onavas, Sonora.
Artificial skull deformation is known to have been practiced by the Chinookan tribes of the U.S. Northwest and the Choctaw of the U.S. Southeast. Shown here, a painting by Paul Kane, showing a Chinookan child in the process of having its head flattened, and an adult after the process.
A deformed skull dating to between 200 B.C. and 100 B.C. and belonging to an individual of the Nazca culture, which flourished along the Peruvian coast.