Archeologists in Mexico have announced an unprecedented find of at least 50,000 relics in a previously unexplored tunnel beneath a key pyramid and temple structure at Teotihuacan, the ancient ceremonial center on the outskirts of Mexico City.

Mexico's National Institute of Anthropology and History, or INAH in Spanish, said in a special symposium last week that the excavation of the tunnel may eventually lead to crucial burial chambers directly beneath the Temple of the Feathered Serpent, the third largest pyramid at Teotihuacan after the Pyramid of the Sun and the Pyramid of the Moon.

The discovery is called the most important single find of artifacts at the site in just over 100 years of its study