Early Olmec culture, centered around the San Lorenzo Tenochtitlán site, a simple farming village located on the Rio Chiquito near the coast in southeast Veracruz, had emerged by 1600-1500 BCE.

The earliest evidence for Olmec culture is found at nearby El Manati, a sacrificial bog with artifacts dating to 1600 BCE or earlier.

Sedentary agriculturalists had lived in the area for centuries before San Lorenzo developed into a regional center.

The first Mesoamerican civilization, the Olmec lay many of the foundations for the civilizations that follow.

Among other "firsts,” there is evidence that the Olmec practiced ritual bloodletting and played the Mesoamerican ballgame, hallmarks of nearly every subsequent Mesoamerican society.

The Olmec, whose name means "rubber people" in the Nahuatl language of the Aztecs, are strong candidates for originating the Mesoamerican ballgame so prevalent among later cultures of the region and used for recreational and religious purposes.

A dozen rubber balls dating to 1600 BCE or earlier have been found in El Manatí, an Olmec sacrificial bog ten kilometers (six point two miles) east of San Lorenzo Tenochtitlan.

These balls predate the earliest ballcourt yet discovered at Paso de la Amada, circa 1400 BCE, although there is no certainty that they were used in the ballgame.

Distinctive features associated with what we call the Olmec culture first appear within the city of San Lorenzo Tenochtitlán around 1400 BCE.

The rise of civilization here is assisted by the local ecology of well-watered alluvial soil, as well as by the transportation network that the Coatzacoalcos River basin provides.

The Olmec people, tribes of sedentary seed gatherers, have settled in villages along the coastal plain at the southwestern edge of the Gulf of Mexico in the tropical lowlands of south-central Mexico, roughly in what are the modern-day states of Veracruz and Tabasco on the Isthmus of Tehuantepec.

The rise of civilization here is probably assisted by the local ecology of well-watered rich alluvial soil, encouraging high maize production.

This ecology may be compared to that of other ancient centers of civilization: the Nile, Indus, and Yellow River valleys, and Mesopotamia.

Olmec history originated at its base within San Lorenzo Tenochtitlán, where distinctively Olmec features had begun to emerge before 1200 BCE.

It is thought that the dense population concentration at San Lorenzo encouraged the rise of an elite class that eventually ensured Olmec dominance and provided the social basis for the production of the symbolic and sophisticated luxury artifacts that define Olmec culture.

Many of these luxury artifacts, such as jade, obsidian, and magnetite, came from distant locations and suggest that early Olmec elites had access to an extensive trading network in Mesoamerica.

The source of the most valued jade, for example, is found in the Motagua River valley in eastern Guatemala, and their obsidian is mainly from sources also in the Guatemala highlands, such as El Chayal and San Martín Jilotepeque, or in Puebla, distances ranging from 200 to 400 km away (120 – 250 miles away) respectively.

Olmec civilization, centered on the southern Gulf Coast of Mexico, is by 1200 BCE fully developed at San Lorenzo, the first great civic and ceremonial center in North America.

San Lorenzo seems to have been largely a ceremonial site, a town without city walls, centered in the midst of a widespread medium-to-large agricultural population.

The ceremonial center and attendant buildings could have housed fifty-five hundred while the entire area, including hinterlands, could have reached thirteen thousand.

Dominating trade routes that extend from the present Mexican state of Guerrero to present Costa Rica, passing through Maya regions, the Olmecs build massive public works projects, including clay building platforms, stone pavements and drainage systems.

Built on some seven hundred hectares of high ground between then-active tributaries, the core of San Lorenzo covers fifty-five hectares that are further modified through extensive filling and leveling; by one estimate half-a-million to two million cubic meters of earthen fill were needed, moved by the basketload.

San Lorenzo also boasts an elaborate drainage system using buried, covered, and channeled stones as a type of "pipe.” It is thought that while San Lorenzo controlled much of, if not all, the Coatzacoalcos basin, areas to the east (such as the area where La Venta will rise to prominence around 900 BCE) and north-northwest (such as the Tuxtla Mountains) were home to independent polities.

The Olmec culture was first defined as an art style, and this continues to be the hallmark of the culture.

Wrought in a large number of media—jade, clay, basalt, and greenstone among others—much Olmec art, such as the Wrestler, is surprisingly naturalistic.

Other art, however, reveals fantastic anthropomorphic creatures, often highly stylized, using an iconography reflective of a religious meaning.

Common motifs include downturned mouths and a cleft head, both of which are seen in representations of were-jaguars.

San Lorenzo Tenochtitlán, the first Olmec center, is best known today for the colossal stone heads unearthed here, the greatest of which weigh twenty tons or more and are three meters high.

The Olmecs produce two characteristic types of stone objects: small jade carvings and colossal basalt monuments.

The unavailability of either type of stone in the coastal plain of the Gulf of Mexico, where the Olmec construct their centers, makes Olmec art enormously difficult to produce.

This aspect of Olmec culture depends on the organization of masses of people.

They must first locate the rare types of stone demanded by the rulers, then transport the stone to their capitals, then spend the thousands of hours needed to shape and finish the work, and finally install the art where the rulers and their religious consultants ordain that it be placed.

The basalt blocks used for the Olmec monuments, each of which weighs several tons, come from the Tuxtla volcanic range, located far north of the Olmec sites.

Transported partially by rafts, the blocks mist also be dragged many kilometers overland, presumably by platoons of laborers.

The artisans laboriously carve the hard, dense stone into enormous naturalistic portraits of Olmec rulers' heads or into colossal, muscular seated figures.

The Olmecs depict the image of the jaguar, ubiquitous in their art, either as an abstract face or as a naturalistic pouncing animal.

In the opinion of some experts, a jaguar's paw is the model for the high platform—formed of millions of basketfuls of earth—on which San Lorenzo sits.

The primitive form of agriculture practiced by the Olmec communities leads to deforestation, which causes soil erosion.

A wholesale destruction of many San Lorenzo monuments also occurs circa 950 BCE, which may point to an internal uprising or, less likely, an invasion.

According to he latest thinking, however, environmental changes may have caused this shift in Olmec centers, with certain important rivers changing course.

San Lorenzo is all but abandoned around 900 BCE at about the same time that La Venta rises to prominence.

San Lorenzo, the center of early Olmec culture, suffers a drastic cultural decline about 900 BCE, probably due to depredations by migrating peoples from the north.

About the time of the center’s decline, the Olmecs bury within the site’s huge artificial ridge, which forms the city’s core, colossal human heads carved of stone, the greatest of which weigh twenty tons or more and are three meters high.

The largest city in Mesoamerica from roughly 1200 BCE to 900 BCE, San Lorenzo seems to have been largely a ceremonial site, a town without city walls, centered in the midst of a widespread medium-to-large agricultural population.

The ceremonial center and attendant buildings could have housed fifty-five hundred while the entire area, including hinterlands, could have reached thirteen thousand.

Although the original site was at a higher elevation than the surrounding countryside, it was further modified through extensive filling and leveling; by one estimate half-a-million to two million cubic meters of earthen fill were needed, moved by the basketload.

San Lorenzo also boasts an elaborate drainage system which uses buried, covered, channeled stones as a type of "pipe".

Some researchers have inferred that the purpose of this system was not only to provide drinking water for the population but for ritual purposes as well, and that the rulership was "intimately linked to the figure of a patron water supernatural.” (Cyphers, Ann (1999) "From Stone to Symbols: Olmec Art in Social Context at San Lorenzo Tenochtitlán", in Social Patterns in Pre-Classic Mesoamerica, Dumbarton Oaks, Washington, D.C., pp. 155 – 181.)