Gran Pirámide de Cholula (Tlachihualtépetl)

The Gran Pirámide de Cholula, known in Nahuatl as Tlachihualtépetl ("hand-made mountain"), sits in San Pedro Cholula in the state of Puebla and is recognized by archaeologists as the largest pyramid by total volume in the world, exceeding the Great Pyramid of Giza in base area. Construction began around 300 BCE during the Formative period and continued in at least four major superimposed phases through the Classic and Postclassic periods, with each generation of builders enclosing the previous structure inside a larger one rather than demolishing it. By the time of the Spanish arrival in 1519, the mound had been overgrown with vegetation and was mistaken for a natural hill, which is why Hernán Cortés ordered a church built on top rather than the pyramid being razed like other Cholula temples. Roughly eight kilometers of tunnels excavated by archaeologists since the 1930s run through the interior, exposing painted murals, altars, and stone staircases from different building stages, and a portion of these tunnels is open to visitors as a walk-through archaeological corridor. The attached Museo de Sitio displays the "Bebedores" mural fragment depicting a pulque-drinking ritual scene, along with ceramics and offerings recovered from the excavations. Interpretation at the site is organized chronologically, moving visitors from the earliest adobe-and-stone core through later stucco-faced platforms to the colonial church that still functions as an active parish above. The exterior plaza, partially reconstructed on the pyramid's western side, shows talud-tablero style stonework typical of the wider Cholula-Teotihuacan cultural sphere. INAH manages ongoing conservation of the tunnel system and the exposed façades, and access to some tunnel sections is periodically restricted for stabilization work.