The construction of the Pyramids of the Sun and Moon at Teotihuacán laid the foundations for the birth and expansion of Mesoamerica’s premier urban center and monumental civic-ceremonial complex.

Situated in the northeast portion of the Basin of Mexico, the ancient metropolis of Teotihuacán was touted by the later Aztecs as the Place Where Men Became Gods. During the period of its earliest urban development—from 150 b.c.e. to 100 c.e.—Teotihuacán grew exponentially and came to encompass a population of some 90,000 people living within an urban landscape extending over an area of 7.5 square miles (20 square kilometers). In fact, so awesome were the monuments of the central axis of the Street of the Dead, with its Pyramids of the Sun, Moon, and Feathered Serpent, that both contemporary peoples and their descendants adopted key elements of the Teotihuacán architectural tradition for centuries to come across the length and breadth of ancient Mesoamerica.

The earliest evidence for those Mesoamerican architectural developments that culminate with the construction of the Pyramids of the Sun and Moon centers on the building of a massive causeway identified with the Street of the Dead. The construction of the core area of the 1.25-mile-long (2.5-kilometer-long) Street of the Dead was completed c. 50 c.e. The layout and building of the causeway represent the earliest civic-ceremonial planning identified with Teotihuacán. The Street of the Dead soon became the focal point for all future civic-ceremonial planning and served to structure and balance the course and character of those architectural and social developments—including the construction of some five thousand known structures—that served to define the metropolis of Teotihuacán.

The Pyramid of the Sun, also known as the Sun Pyramid, was completed c. 125 c.e. The monument was built during the course of two primary construction episodes that culminated with the erection of an earlier version of the Sun Pyramid. Built of rubble-core masonry with an adobe-block and lime-plaster veneer, the nucleus of the Sun Pyramid was stabilized through the use of massive timbers and task walls, or cell construction, used to control against the lateral flow of masonry and rubble-fill materials. The otherwise fluid nature of rubble-fill construction was checked through the inclusion of task walls, timbers, and related reinforcements that also provided safeguards against the nearly constant seismic activity in the region. The final stage of construction expanded the earlier monument from one measuring 600 square feet (56 square meters), with a height of 150 feet (46 meters), to one measuring 700 square feet (65 square meters) at its base and rising to a staggering height of 212 feet (65 meters). Incredibly, much of that construction identified with the Sun Pyramid occurred during the course of a single century, and the monument itself contains 35 million cubic feet (1 million cubic meters) of fill. That the peoples of Teotihuacán constructed their many temples—and mobilized work parties to move stones weighing between 22 and 200 tons—without the aid of draft animals or wheeled vehicles most likely earned them the admiration and wonder of many of the successor states of the Valley of Mexico and beyond.

Excavations by Rubén Cabrera Castro of Mexico’s Instituto Nacional de Antropología e Historia—in collaboration with Saburo Sugiyama and George Cowgill of Arizona State University—indicate that the Pyramids of the Sun and Moon were raised to house the funerary remains of the elite overlords of the ancient metropolis. Given that initial construction of the Pyramid of the Moon antedates that of the Sun, the architect (or architects) of the original master plan are most likely buried within the Pyramid of the Moon. Moreover, the hundreds of sacrificial captives bound and buried within the nucleus of the Feathered Serpent Pyramid clearly attest that the construction of these monuments was fraught with political and military overtones during the period extending from 100 to 200 c.e.

Within and about the base of the Sun Pyramid are strewn remnants of monumental stonework that once adorned the facade of that great structure. Included within the iconographic conventions of surviving sculpture and masonry from the forecourt and facade of the Sun Pyramid are images of human skulls surrounded by circular sun shields or spoked wheels, immense representations of feathered serpents or rattlesnake motifs, and a host of architectural elements and remnants of painted plaster that similarly once adorned the massive Sun Pyramid. In its heyday, the Sun Pyramid boasted an ornate masonry and painted stucco facade of alternating sun shields, human skulls, rattlesnakes, and painted frescoed murals depicting priests, warriors, sacred animals or mascots such as the jaguar or ocelotl, representations of a tripartite creature thought to symbolize the planet Venus, and a host of human and nonhuman forms and other cosmological themes. Atop its 212-foot (65-meter) summit, a massive, colorful and ornate temple sanctuary or civic-ceremonial enclosure is thought to have risen an additional 40 feet (12 meters) above the summit of the platform in the period before the site’s burning and destruction in 650 c.e. If images from ceramics, sculpture, and frescoes are any indication, then an ornate series of fired clay and stucco frieze elements and wall panels depicting undulating serpents, water lilies, and related imagery—like those recovered from excavations at the nearby Feathered Serpent Pyramid—probably graced the facade of the temple or sancta sanctorum located atop the summit of the Sun Pyramid.

One other particularly unusual dimension of the Sun Pyramid’s architectural history centers on the fact that the whole of the monument was constructed immediately atop a natural cavern that extends some 330 feet (100 meters) in overall length beneath the pyramid’s base. The natural cavern was modified at successive intervals, and slabs were used to diminish the height or narrow the passage into the cave. Additional modifications resulted in the opening of six cavernous enclosures, two of which were located at the midpoint of the cavern. An additional four were carved from the walls of the largest chamber, located at the eastern end of the cavern complex. The cavern located beneath the Sun Pyramid was so important that the axis of the Sun Pyramid was aligned with that of the cavern from the onset of construction. The significance of caverns in Mesoamerican cultural history and belief—with their underworld associations and ancestral and supernatural linkages to the cosmic order—suggests that the cave beneath the Pyramid of the Sun was intended to complement that course of civic planning that linked the metropolis of Teotihuacán to the cosmological order of the ancient world.

Given the extent of that iconography devoted to Teotihuacán representations of the Sun, Moon, Venus, and the stars, it should come as no surprise that scholars have identified key architectural alignments and placements correlated with astronomical phenomena deemed significant to the zenith passage of the Sun’s transit. The implications and potentials for rediscovering and interpreting the significance of cosmological and astronomical relationships among the Pyramids of the Sun and Moon and the Street of the Dead have yet to be fully realized.

The end of this period of monumental construction was marked by the building and completion of the Feathered Serpent Pyramid c. 200 c.e. In fact, the construction of the Feathered Serpent monument marked the erection of the last major monument to be built in the ancient metropolis. Although archaeologist Saburo Sugiyama believes that the construction of the Feathered Serpent Pyramid may represent the first use of the hallmark talud-tablero architectural form, described as a recessed tablet situated atop a sloping basal platform; archaeologist Angel García Cook argues for a much earlier appearance of that style at the site of Tlalancaleca in the region of Puebla in 200 b.c.e. This early date for the appearance of the talud-tablero architectural style disagrees with other comparable dates and findings reported in the literature. Nevertheless, the use of a construction-cell system—or task walls—erected within the nucleus of the monuments in question followed preexisting modes of construction specific to earthquake-resistant architectural features known from throughout those regions within which Teotihuacán and its allies served as key cultural and political protagonists.

The Street of the Dead was ultimately expanded some seventy-five to one hundred years after completion of the Sun Pyramid in 125 c.e. Much of the construction that occurred in the earliest years of the metropolis centered on the Street of the Dead and the civic-ceremonial heart of the city most closely associated with the monuments of the Sun and Moon. Not until the period extending from 150 to 225 c.e. were residential compounds built beyond the civic-ceremonial core of Teotihuacán. During the course of the next several centuries, Teotihuacán’s political, commercial, and military might and prestige grew by leaps and bounds, and its wide-ranging influence was felt in many of the major Mesoamerican cities. The talud-tablero architectural tradition that is argued to have originated in 200 c.e. was soon thereafter adopted in major urban centers and outposts of Teotihuacán found throughout Mesoamerica. In 650 c.e., the palatial estates bordering the Street of the Dead and the towering monuments of the Sun and Moon were reduced to ruin in a conflagration that ultimately claimed the lives of a number of the most prominent, powerful, and elite overlords of the ancient metropolis of Teotihuacán.

• Berrin, Kathleen, and Esther Pasztory, eds. Teotihuacan: Art from the City of the Gods. New York: Thames and Hudson, 1993. A collection of articles regarding the architectural murals and art history of the ancient metropolis of Teotihuacán.
• Margain, Carlos R. “Pre-Columbian Architecture of Central Mexico.” In Archaeology of Northern Mesoamerica, Part One, edited by Gordon F. Ekholm and Ignacio Bernal. Vol. 10 in Handbook of Middle American Indians. Austin: University of Texas Press, 1971. A detailed assessment and summary of the architecture of Teotihuacán and highland Central Mexico.
• Millon, René. “Teotihuacan Studies: From 1950 to 1990 and Beyond.” In Art, Ideology, and the City of Teotihuacan, edited by Janet Catherine Berlo. Washington, D.C.: Dumbarton Oaks Research Library and Collection, 1992. Provides a detailed survey of the many scholarly contributions that serve to frame the archaeological study of Teotihuacán and its art historical and architectural treasures.
• Price, T. Douglas, and Gary M. Feinman. “Teotihuacan: One of the World’s Largest Cities in a.d. 500.” In Images of the Past. 3d ed. Mountain View, Calif.: Mayfield, 2001. An introductory level overview of recent perspectives on the urbanization and growth of ancient Teotihuacán.
• Sprajc, Ivan. “Astronomical Alignments at Teotihuacan, Mexico.” Latin American Antiquity 11, no. 4 (2000): 403-415. Provides a detailed analysis of the author’s contentions that the Pyramid of the Sun and the Ciudadela complex were located so as to provide a basis for alignments with deliberate and astronomically functional orientations.
• Sugiyama, Saburo. “Burials Dedicated to the Old Temple of Quetzalcoatl at Teotihuacán, Mexico.” American Antiquity 54, no. 1 (1989): 85-106. An initial reporting of what ultimately proved to represent a mass burial of sacrificial victims under the Feathered Serpent Pyramid of Teotihuacán, Mexico.