Portal to Maya Underworld Found in Mexico?

National Geographic reports on "a maze of stone temples in underground caves, some submerged in water and containing human bones" that, archeologists think, may have been portals "for dead souls to pass into the underworld."
Archaeologists Victoria Rojas (front) and Lara Hindersten (back) work at a site in the village of Tahtzibichen, in Mérida, the capital of Mexico's Yucatán state, on April 12, 2008.