What is the large civilization that is the cultural hearth in southern Mexico?

The large civilization that is considered the cultural hearth in southern Mexico is the Olmec civilization. Flourishing around 1200 to 400 BCE, the Olmecs are known for their significant contributions to Mesoamerican culture, including monumental stone carvings, a complex social structure, and early forms of writing and calendar systems. Their influence set the foundation for later civilizations such as the Maya and Aztecs. Key archaeological sites associated with the Olmecs include San Lorenzo and La Venta.