The Ruins of a Great Civilization Located in the heart of Mexico City, Templo Mayor is something of a hidden gem. Prior to the arrival of the Spanish Conquistadors much of Mexico was under the control of the Aztec Empire. The city of Tenochtitlan was at the heart of this massive empire, and with an estimated population of a quarter of a million inhabitants Tenochtitlan would have been one of the largest cities in the world when the Spanish arrived. Today all that remains visible of this vibrant metropolis are the ruins of the city’s great temple – El Templo Mayor. Hidden in Plain Sight Just steps from the Mexico…