The two stone monuments depict local Olmec rulers and are at least 2,500 years old (Late Olmec period). The 2,500-year-old Olmec relief from the state of Tabasco, south-eastern Mexico. Image credit: INAH Tabasco Center. The Olmecs were the earliest known major civilization in the Mesoamerica. They flourished during Mesoamerica’s formative period, dating from as early as 1600 BCE to about 400 BCE. They lived along the Gulf Coast of Mexico in the...