In an artist's recreation of the Aztecs' island capital, grand temples rise in the sacred precinct behind the main market.
When Spanish conquistador Hernán Cortés arrived in 1519, Tenochtitlan — with a population that may have approached 300,000—was one of the world's ten largest cities.
The Spaniards were astounded.
"We were struck with the numbers of canoes, passing to and from the mainland, loaded with provisions and merchandise...." wrote Bernal Díaz del Castillo, a soldier who accompanied Cortés.
"The noise and bustle of the market-place below us could be heard almost a league off, and those who had been at Rome and at Constantinople said, that for convenience, regularity, and population they had never seen the like."