A true highlight outside of Mexico City is Teotihuacan. It was the largest city in the pre-Columbian Americas established in 100 BCE. The Pyramid of the Sun and Pyramid of the Moon are most notable, with many other smaller pyramids lining the Avenue of the Dead. What you can visit is only 10% of the original city, most of which still lies unexcavated under earth mounds. The city had about 125,000 inhabitants at its peak. The third largest temple is the Temple of the Feathered Serpent which represents the Aztec god Quetzalcoatl.