What civilization is known as the earliest in Mexico, thriving in rainforests and developing a calendar?

The Olmecs are recognized as one of the earliest civilizations in Mexico, flourishing in the lowland rainforests of present-day Veracruz and Tabasco. Emerging around 1200 BCE, the Olmec culture is notable for its significant contributions to Mesoamerican civilization, including the development of large-scale urban centers, monumental architecture, and a complex social structure. They are often credited with establishing one of the first known Mesoamerican writing systems and are famous for their distinctive colossal heads sculpted from basalt.

Additionally, the Olmecs are known for developing a calendar system, which later influenced subsequent cultures in the region. Their advancements laid the groundwork for later civilizations in Mexico, such as the Mayans and Aztecs, who would build upon their innovations in various aspects of society, religion, and astronomy. In this context, the Olmecs' role as a precursor to later civilizations highlights their importance in the historical narrative of Mesoamerica.