The Temple of the Feathered Serpent is the third largest pyramid in Teotihuacan, Mexico.

A "re-creation of the underworld" discovered in the Mexican city of Teotihuacan has been hailed as one of the most important archaeological discoveries of the century. The passage was found buried under the Temple of the Quetzalcoatl (feathered serpent) by radar technology.

The tunnel, first discovered in 2003, was believed to have been sealed over 1,800 years ago by the pre-Hispanic people of the region with intent to stay sealed for eternity, but modern technology has allowed scientists and archaeologists to unearth more and more. The exploration team is working on a map of the tunnel, which is believed to be around 120 meters long.

Several burial chambers are located near the end of the passage, said to be rulers of the ancient Teotihuacan people whose city remains only around 5% excavated despite nearly a century of explanation. Roughly 200 sacrificial victims were also buried under the tomb. The area was said to have been one of the most populous parts of pre-Hispanic America.