By Miguel Angel Gutierrez

MEXICO CITY (Reuters) - Mexican archeologists have discovered a maze of stone temples in underground caves, some submerged in water and containing human bones, which ancient Mayans believed was a portal where dead souls entered the underworld.

Clad in scuba gear and edging through narrow tunnels, researchers discovered the stone ruins of eleven sacred temples and what could be the remains of human sacrifices at the site in the Yucatan Peninsula.

Archeologists say Mayans believed the underground complex of water-filled caves leading into dry chambers -- including an underground road stretching some 330 feet -- was the path to a mythical underworld, known as Xibalba.