Pyramid of the Sun

19.6925°N, 98.8438°W.

The Pyramid of the Sun at Teotihuacan, in the Valley of Mexico approximately 50 kilometres northeast of modern Mexico City. The largest pyramid in Mesoamerica and the third-largest pyramid in the world by volume after Cholula and the Great Pyramid of Giza. Construction was carried out in two principal phases between approximately 100 CE and 250 CE; the structure was built atop a natural lava-tube cave system that the Teotihuacanos modified into a four-petaled chamber, discovered in 1971 during excavation of the central staircase. Original base 224 metres per side; original height 75 metres on five terraces — substantially smaller than the Great Pyramid but covering nearly the same ground area. The pyramid is oriented 15°25′ east of north, an alignment that matches sunset on the day the sun passes through the zenith at this latitude (12 August) and references the Pleiades at heliacal rising. The builders abandoned the city in the seventh century CE; their language, ethnic identity, and writing system have never been recovered.

The largest pyramid in the Americas, built over a ritual cave, by a civilisation that named its city only in retrospect — Teotihuacan is the Aztec word for the place where the gods were born, applied a thousand years after the builders walked away.