A breakthrough LiDAR survey across the rugged Tehuantepec Isthmus has identified a previously unknown urban network that served as a cultural and economic bridge between the Olmec heartland and the rising Zapotec centers. The survey detected over 4,000 individual structures, including massive earthen pyramids, residential terraces, and a sophisticated concentric causeway system that facilitated trade across the narrowest part of Mexico.
The data suggests that this 'megalopolis' was a thriving hub for the exchange of obsidian, jade, and cacao as early as 1000 BCE. The urban layout combines the massive ceremonial plazas typical of the Olmec with the defensive hilltop positioning favored by the Zapotecs, providing the first physical evidence of a prolonged cultural synthesis between these two foundational Mesoamerican civilizations. This discovery forces a significant revision of the timeline for large-scale urbanism in the region.