Try to imagine standing here almost two thousand years ago. In front of you, a mountain rises—but it's not a natural one, it was built by human hands. More than 65 meters tall, with a base of roughly 225 meters on each side. This is the Pyramid of the Sun: Teotihuacan's largest structure, and one of the most awe-inspiring constructions of the entire ancient world.

But its significance goes beyond its size. This pyramid is key to understanding how one of the most complex and sophisticated cities of Mesoamerica functioned.

Building the pyramid

The Pyramid of the Sun was built during Teotihuacan's earliest phases, as part of a large-scale urban development program. Its core consists of compacted agricultural soil—which distinguishes it from the Pyramid of the Moon—along with stone and volcanic materials, all later covered with stone walls and layers of painted stucco, most likely in white and red. This construction method made it possible to raise a structure of such monumental proportions through the coordinated labor of large groups of people.

Archaeologists have discovered offerings deposited during the construction of the pyramid, revealing something important: the process of building it was not merely an engineering feat—it was also a ritual act. At each corner and level of the structure, the remains of sixteen ritually sacrificed children were found, placed there as offerings.

Located along the city's central axis, the Pyramid of the Sun was part of a carefully planned urban system—a city laid out with remarkable precision, organizing avenues, temples, and residential areas into a coherent whole. It was not just an immense building; it was a statement about how the world was ordered. From this point, the city, the landscape, and the cosmos all came together as part of a single interconnected system of meaning.

Origin of its name

Here's something worth knowing: Pyramid of the Sun is not the original name of the building. Centuries after Teotihuacan was abandoned, the Mexica peoples arrived at the site and made sense of it through their own worldview. They believed this was the place where the sun and moon were created, and they called the structure Tonatiuh Itzacual, roughly "enclosure of the Sun."

What the city’s original inhabitants called it remains unknown. But the pyramid's orientation, however, offers important clues: its main facade faces west, toward the setting sun, and astronomical research has confirmed that this alignment corresponds to key dates in the solar calendar.

Religion and the pyramid

For centuries, this was one of the most important spaces in the city. Teotihuacan's center was defined by monumental architecture tied to ritual and to the symbolic structures of power. The Pyramid of the Sun appears to have served as the main stage for public ceremony, a place where religious and political life merged: a state temple, essentially.

Some excavations have uncovered offerings and ritual remains associated with rain, fertility, and natural forces, raising the possibility that the pyramid was linked to an early storm deity, perhaps a precursor to Tlaloc. However, there is still no conclusive evidence identifying the deity to whom the pyramid may have been dedicated, if it was dedicated to one at all.

Another interpretation goes even further: the pyramid as a sacred mountain. In Mesoamerican thought, mountains were where water, seeds, and life originated—repositories of natural and spiritual energy, and points of contact between the different layers of the universe. From this perspective, the Pyramid of the Sun may have represented the world itself: a man-made mountain embodying the cosmic order.

The tunnel and chambers beneath

Directly beneath the pyramid lies an excavated tunnel leading to four chambers, aligned with the structure above. This underground space predates the pyramid and has been interpreted as a place of deep ritual significance, possibly tied to founding ceremonies or to concepts surrounding the origin of the world. In Mesoamerican thought, tunnels and caves—especially those associated with water, as this one likely was—evoke the moment of creation: the primordial time before anything existed. The pyramid does not merely rise toward the sky; it also extends downward into the underworld, reinforcing its role as the symbolic axis of the universe.

The pyramid and the stars

The Pyramid of the Sun features numerous astronomical alignments corresponding to key dates in the Mesoamerican calendar, suggesting that it may also have functioned as a precise astronomical instrument. One such alignment occurs on February 12th, a date associated with the beginning of the Mesoamerican calendar and situated 52 days after the winter solstice; October 29th marks another alignment, this time 52 days before the winter solstice, closing the cycle. Additionally, August 13th brings an alignment with the setting sun on the western horizon, a date tied to the Long Count Calendar; and April 29th marks the midpoint of the annual solar cycle. Solstice alignments have also been documented.

Today, the Pyramid of the Sun still dominates the valley landscape. Visible from kilometers away, it remains surrounded by unanswered questions. In many ways, that seems fitting, because it continues to function much as it did two thousand years ago: as a meeting point between what we know and what we are still striving to understand.

Visiting today

Enter through Gate 2 and the pyramid will appear directly before you, rising against the sky. Walk along at least two of its sides—the only way to really appreciate its scale.