Final answer:
The earliest traces of Olmec civilization date back to around 1350 BCE in Veracruz, Mexico, where they built monumental structures and influenced subsequent Mesoamerican cultures.
Step-by-step explanation:
The earliest traces of Olmec civilization are found at the San Lorenzo site in the state of Veracruz, Mexico, dating back to approximately 1350 BCE. This civilization was known for constructing a massive earthen platform amid woodland plains that frequently experienced flooding. The Olmecs are regarded as a critical precursor to later Mesoamerican civilizations such as the Maya and the Aztecs, and through their innovations in art, architecture, and society, they laid the groundwork for the rich cultures that would follow. The legacy of the Olmec civilization includes monumental stone sculptures, the development of a calendar system, a unique form of government, and intricate trade networks that extended throughout Mesoamerica