Teotihuacan is one of the most complex and extensive archaeological sites in Mesoamerica, and the challenge of preserving it is proportional to its scale. That challenge extends well beyond protecting the great visible structures.

The Pyramids of the Sun and Moon, the Feathered Serpent Temple, and the Avenue of the Dead draw millions of visitors every year—but the pre-Hispanic city actually extends beneath the streets, homes, agricultural fields, and workshops of the communities living in the valley today. This makes Teotihuacan a living territory, where past and present coexist in an ongoing and delicate relationship.

Because the major monuments occupy the center of the ancient city, the federal government has been able to directly protect that core area. The rest of the pre-Hispanic urban fabric—residential neighborhoods, streets, craft production areas, and agricultural zones—remains buried beneath contemporary settlements. Conservation therefore requires differentiated strategies depending on the zone, with levels of intervention ranging from direct management by the Instituto Nacional de Antropología e Historia (INAH) to active participation by municipal governments and local communities.

One of the most important tools for day-to-day conservation is Salvage Archaeology—an excavation methodology developed specifically for situations where construction or infrastructure work, such as pipe installation, road widening, or new building foundations, puts buried archaeological evidence at risk. These interventions allow specialists to document and recover structures, objects, and burial contexts that would otherwise be lost permanently.

Today, site conservation also includes reforestation efforts, height regulations for new construction, and the maintenance of the valley's cultural landscape—understood as a heritage value in its own right, as significant as the monuments it frames.

The legal framework protecting Teotihuacan originates in the Archaeological Monuments Zone Decree, a document developed by specialists in archaeology, topography, and law. It precisely defines the boundaries of the area through a protection polygon, identifies those responsible for its stewardship, and establishes the specific measures required to ensure the integrity of both movable and immovable archaeological remains—including human remains and flora and fauna associated with pre-Hispanic cultures.

Teotihuacan's decree was published in 1988. Its protected area covers almost 3,382 hectares, making it one of the largest archaeological monument zones in the country. This document divides the protected territory into three areas with distinct characteristics and protection regimes. Area A comprises the excavated archaeological core open to the public, administered entirely by INAH. Area B serves as a buffer zone around the central core, where new construction and the expansion of existing buildings are prohibited. Area C corresponds to the territories inhabited by present-day communities, where urban development may continue under regulated conditions—provided that the relevant authorities are notified before any work begins, so that an archaeological team can intervene if necessary.

These provisions are complemented by the urban development plans and urban image regulations of the municipalities of Teotihuacan and San Martín de las Pirámides, which govern permitted land uses and maximum building heights, ensuring that local community growth remains compatible with the presence of one of the world's most significant archaeological heritage sites.

Teotihuacan's importance in the landscape of global cultural heritage is immense. At its height, in the early centuries of the Common Era, it was one of the largest cities in the ancient world—covering more than 20 square kilometers and home to an estimated population of over 100,000 people. Its influence spread across much of Mesoamerica, and the remains of its art and architecture, urban organization, and cosmology continue to be studied and interpreted by researchers worldwide.

In 1987, UNESCO inscribed Teotihuacan on its World Heritage List, recognizing its outstanding universal value as testimony to a civilization that durably transformed the cultural development of the American continent.

But the site's heritage significance does not rest on its pyramids and palace murals alone. Beneath the valley's communities lie the neighborhoods where artisans, merchants, priests, and administrators once lived; the domestic spaces that reveal patterns of everyday life; and the material record of exchanges with regions as distant as Oaxaca, the Gulf of Mexico, and western regions of the country. Every ceramic fragment, every bone, every trace of a buried wall contributes an indispensable piece to the puzzle of a culture that, despite centuries of research, still holds numerous secrets.

This heritage belongs not only to Mexico but to all of humanity. Its preservation is an intergenerational commitment—the obligation to pass on to future generations a legacy that was not created by us, but that we are in a position to protect or damage depending on the decisions we make today.

Protecting Teotihuacan is not an exclusive responsibility of government institutions. On the contrary, the scale and complexity of the site mean that the active participation of every individual—valley resident, national visitor, or international tourist—is essential for conservation efforts to be truly effective.

For those living in the valley communities:

Contributing to heritage care starts with notifying the relevant authorities before beginning any construction, expansion, or repair work on your property. This allows specialized teams to intervene in time to document and preserve whatever remains may lie beneath the ground.

Keeping streets and community spaces in good condition, respecting building height regulations, and actively participating in valley reforestation programs are concrete and valuable contributions to the care of the cultural landscape.

For visitors:

Respecting the site starts with closely following the guidance of INAH staff working in the archaeological zone. These individuals—most of them from the valley itself—know the site with a depth that goes well beyond academic knowledge, and their work is essential to ensuring that every visit takes place without causing damage to the site.

Beyond following their guidance, visitors can contribute by refraining from climbing structures not designated for that purpose, not taking any fragment of archaeological material—however small or seemingly insignificant—disposing of waste in designated areas, and respecting signage and access limits.

In a broader sense, caring for Teotihuacan also means valuing the site beyond its visual spectacle: approaching its history with genuine curiosity, supporting the educational and cultural initiatives that develop around it, and passing on to others—especially children and young people—the understanding that this exceptional place is a shared heritage whose future depends, in large part, on the everyday decisions of those who inhabit it, visit it, and manage it.