Archaeologists in Mexico have discovered an ancient canal network under the 13-hundred-year-old Temple of the Inscriptions in the Mayan ruins.
Researchers at Mexico's National Institute of Anthropology and History say the canal system was uncovered using sonar technology.
The tunnel network has different levels and still has running water. Scientists believe the canal may be a symbolic gateway to the Underworld for one of the world's most mysterious lost civilizations.
The Mayans lived in an area that encompasses southeastern Mexico, all of Guatemala and Belize. They developed hieroglyphic writing, a calendar and astronomical system.