One of the first Mesoamerican societies, the Olmec inhabited the tropical lowlands of south-central Mexico.
The first signs of the Olmec are around 1400 BC in the city of San Lorenzo, the main Olmec settlement which was supported by two other centers, Tenochtitlan and Potrero Nuevo.
The Olmec were master builders with each of the major sites containing ceremonial courts, house mounds, large conical pyramids and stone monuments including the colossal head that they are most known for.
Because they were one of the earliest and most advanced Mesoamerican cultures at the time, they are often considered the mother culture of many other Mesoamerican cultures.
Around 400 BC the eastern half of the Olmec's lands was depopulated- possibly due to environmental changes.
They may have also relocated after volcanic activity in the area. Another popular theory is that they were invaded, but no one knows whom the invaders might be.