About forty kilometres northeast of Mexico City, the remains of Teotihuacan rise from a broad valley beneath the surrounding mountains. Walking among its enormous pyramids, it is easy to imagine a single, powerful civilisation responsible for everything we see. Yet the identity of the city's founders remains one of its most intriguing questions. Teotihuacan was established centuries before the rise of the Aztec Empire, probably around the first century BCE. Its inhabitants left no securely deciphered written history naming their rulers or explaining their origins. Archaeologists see a complex, multiethnic urban society rather than a city that can confidently be attributed to one known people.
Over the following centuries, Teotihuacan became one of the great cities of the ancient Americas. Its ceremonial heart was organised around the Avenue of the Dead, with the Pyramid of the Moon at its northern end and the immense Pyramid of the Sun rising beside the avenue. Beyond these monuments were residential compounds, workshops, courtyards and painted walls. The city was not simply a gathering of temples: it was a place where families lived, artisans worked and distant communities met. Obsidian from the region travelled along trade networks extending across Mesoamerica.
The Pyramid of the Sun, rising approximately 65 metres above the ground, is particularly striking because of the mystery beneath it. A passage extending more than one hundred metres leads towards chambers under the monument. The underground space existed before the great pyramid was erected and was altered by the city's inhabitants. Some scholars interpret it as a symbolic entrance to the underworld or a place connected with the mythical emergence of life. Others have considered its use for offerings, foundation rites or elite burials. Archaeological investigations have not established a single definitive explanation.
The relationship between the underground passage and the pyramid above is especially revealing. In many Mesoamerican traditions, caves were not merely empty spaces in the earth: they were associated with water, fertility, ancestors and the origins of communities. A monumental pyramid built above such a place may have represented a sacred mountain, joining the visible world to the realm beneath it. What appears from a distance to be a feat of engineering may therefore also have been a carefully conceived religious landscape.
Another discovery helps distinguish archaeological evidence from the legends surrounding the pyramids. Beneath the Temple of the Feathered Serpent, a different tunnel yielded small traces of liquid mercury, which may have represented rivers or lakes of the underworld. Pyrite minerals there could have created a glittering, star-like effect in torchlight. These discoveries belong to the Feathered Serpent complex, not to the passage beneath the Pyramid of the Sun. Claims that the Sun Pyramid’s tunnels were lined with mica or carried flowing rivers of mercury remain unverified.
What was the Pyramid of the Sun used for? The strongest evidence points to ceremonial and political functions rather than an ordinary tomb or an astronomical observatory in the modern sense. Offerings and ritual deposits indicate that its construction and use were bound to religious practices. Its placement and orientation also suggest attention to the movement of the sun and to significant calendrical dates. But the deity originally associated with the monument is still debated. Even its familiar name, 'Pyramid of the Sun', was given long after the city's builders had disappeared.
Teotihuacan's monuments also reveal the scale of organisation required to build them. Stone, volcanic material and compacted earth were assembled into enormous architectural forms, once finished with plaster and colour. The bare surfaces we see today can make the ancient city seem austere. In its own time, painted façades, murals and public ceremonies would have given it a very different appearance, one in which architecture, landscape and belief were closely connected.
By the sixth century, Teotihuacan was undergoing profound change. Parts of its ceremonial centre were damaged by fire, and its political order appears to have weakened. The causes remain contested, with internal conflict, environmental pressures and changing regional relationships among the possibilities discussed by researchers. The city did not simply vanish in a single moment, but its period as a dominant urban power came to an end.
Centuries later, the Mexica encountered these ruins and regarded them as a place associated with the creation of the gods and the celestial bodies. That later reverence gave us the name Teotihuacan, often translated as 'the place where the gods were created'. For me, the fascination of photographing the site lies not only in the overwhelming scale of the pyramids, but in the questions they leave unanswered. Above ground, an immense city remains visible; beneath the Pyramid of the Sun, another part of its story is still hidden.