Using high-resolution LiDAR technology, researchers have mapped a previously unknown defensive perimeter surrounding a major Zapotec urban center in the Oaxaca Valley. The survey revealed a five-mile-long stone mega-wall punctuated by 22 fortified watchtowers, designed to control the movement of people and trade across the valley floor. This massive infrastructure project indicates that the Zapotec state was engaged in significant military territorialism and frontier management during the Classic period (approx. 500 CE).
The mapping also identified a hidden system of stepped terraces and ramparts that turned the surrounding hills into a tiered defensive network. This discovery suggests that the Zapotec capital of Monte Albán exerted much more direct physical control over the valley's landscape than previously hypothesized. The scale of the wall suggests a highly centralized labor force capable of moving thousands of tons of stone to secure the city-state's vital agricultural and trade resources.