The Temple of Quetzalcoatl is one of the smaller, yet well-known structures at Teotihuacan.

Mexico City is one of the world's largest cities in modern times -- and just north of it lies one of the largest cities of ancient times. The mysterious origins of the great city of Teotihuacan is just one of the things that make it famous. From a tourist's perspective, however, the city is best known for its stunning pyramids.

Mysterious Origins

The Aztecs named the giant city Teotihuacan -- meaning "birthplace of the gods" -- but members of that relatively modern society were not the ones who built it. No one knows who actually built the structure, but the area was thought to have been settled as early as the second century B.C. At its peak, it was thought to have been home to more than 100,000 residents, who lived in apartment-style dwellings dotted around the pyramid structures. The city was also burned numerous times, for reasons unknown. When the Aztecs discovered it about a thousand years later, it's thought they used it for the sacrificial rituals that were common in Aztec culture.

The Avenue of the Dead

Entering the city, one of the first things you see is the sweeping Avenue of the Dead. The avenue stretches for more than 2 kilometers and serves as the connection between the various temples and structures of the city. Throughout its various periods of use, the avenue was likely a gathering place for people to witness sacrifices or other rituals taking place at the pyramids and temples.

The Pyramid of the Sun

The largest and perhaps most famous structure at the Teotihuacan site is the Pyramid of the Sun. Standing about 200 feet tall, the pyramid was one of the largest structures that was built in the Western Hemisphere in ancient times. Inside the pyramid, excavators have found chambers that were thought to be used for burials or other rituals. Today, you can climb the pyramid's steep steps to the top for a view of the surrounding Valley of Mexico.

Other Structures

Only slightly smaller than the Pyramid of the Sun, the Pyramid of the Moon is the second largest structure in Teotihuacan. Standing at about 150 feet tall, the pyramid includes various platforms that were thought to be the sites of rituals that could be seen from below. Excavators have also found evidence of tombs inside the structure. While the two pyramids are perhaps the most impressive features, the site is also home to many other temples and structures of lesser renown. These include the Temple of the Feathered Serpent, featuring numerous detailed carvings. Throughout the city, there are numerous colorful murals on the walls of the apartment dwellings and temples.