The Aztecs (or Mexica) spread from their original ... But very little is known about who built this remarkable city and its vast pyramids, or even what it was originally called.

Archaeologists have discovered the ruins of an 800-year-old Aztec pyramid in the heart of Mexico City that could show the ancient city is at least a century older than previously thought.

On the edge of Mexico City's famed Zócalo plaza, next to the ruins of the Aztec sacred pyramid known as the Templo Mayor, the remains of an animal—perhaps a dog or a wolf—were discovered.

Scattered throughout Mexico, you'll find the ruins of several ancient civilizations, including those of the Aztec, Maya and Toltec people. Many of these sites feature impressive pyramids standing ...