In the heart of Mexico City is where you will find Templo Mayor, part of the Aztec center of ritual known as the Sacred Precinct in the city of Tenochtitlan. Exposed to the world by the archaeologist Manuel Gamio in 1914 the rest of the Aztec empire remains buried beneath the avenues and buildings of the modern age.
First constructed in 1325, Templo Mayor was at one time a soaring edifice of dual pyramids dedicated to the gods. One pyramid dedicated to the rain and earth god Tlaloc, representing Tonacatepetl the Hill of Sustenance, the other dedicated to the war god Huitzilpochtli, representing his birthplace on the Hill of Coatepec.
Now all that is left is the base of the pyramid and prior versions built by successive rulers buried deep below the earth. The Spanish conquerors dismantled the pyramids to reuse the stone to build their own temple, the Metropolitan Cathedral.
Sources and further reading:
Miller, Mary Ellen. 2012. The Art of Mesoamerica: From Olmec to Aztec. 5th ed. Thomas & Hudson Ltd, London.
The Met Museum Heilbrunn Timeline of Art History on Templo Mayor
Archaeology Magazine article by Roger Atwood
Museum Victoria lecture by Dr. Carlos Javier Gonzalez