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.

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.

Scattered throughout Mexico, you'll find the ruins of several ancient civilizations, including those of the Aztec ... pyramids of its kind in the Western Hemisphere. Those who want to climb to the ...