Center of the religious and political life of the Mexica, in the heart of present-day Mexico City, it contains amazing vestiges of the Templo Mayor (dedicated to Tláloc and Huitzilopochtli), such as a tzompantli altar and the House of the Eagles. Among its treasures is the monolith of the goddess Coyolxauhqui.

The Great Temple was expanded seven times; The last version, the one seen and destroyed by the Spanish, was imposing (about 45 m high on a quadrangular base of about 400 m per side). The pyramid had two long staircases that culminated at the top, in front of each of the two temples dedicated to its main gods: the one in the north in honor of Tláloc ("nectar of the earth"), god of rain and agriculture, and the one in the south to honor Huitzilopochtli ("left-handed hummingbird", "resurrected warrior"), god of war. Before each expansion, the Mexica began a “flowery war” against some enemy nation, to capture captives and sacrifice them on the day of the consecration of the renovated temple.