Imagine yourself deep inside the depths of the earth, waste-deep in chilly water surrounded by mountainous, mystical towers of stalagmites and stalactites, hundreds of bats hanging from above, large freshwater crabs, crayfish, catfish and tropical fish swimming beside you.

A huge black spider lingers nearby in a crevasse revealing itself from the darkness as light from your helmet shines upon an ancient Mayan sacrificial site with a sparkling calcified skeleton.

In the eerie silence and darkness, you find yourself further in the cave-like altar that's strewn about with more skulls, bones and pottery showing "kill holes" intended to allow spirits to escape. This brings your mind to strange places, making you wonder if you will be the next offering to the Gods of the Underworld.

Welcome to "Xibalba," otherwise known as a "place of fear," and "the name of the underworld in K'iche' Maya mythology, ruled by the Maya death gods and their helpers." A place where ancient rituals and sacrifices were made and where Mayans believed the gods who provided rain harvests resided -- or just a place where I vacation.

Sound wild? Well, it is and well-worth a trip to Belize to experience Actun Tunichil Muknal (Cave of the Crystal Sepulchre), or ATM, a true gem and archeologist's dream.

Named the No. 1 on its list of "Sacred Places of a Lifetime" by National Geographic, ATM is located in the Cayo District, not far from the charming little town of San Ignacio. It involves a 45-minute hike, crossing streams and river banks of the Tapir Mountain Reserve to get to the cave's entrance. Once there, you swim, twist and turn and climb to the depths of ATM where there is no natural light.

Now I understand why "Ghost Hunters International" Season 3 dedicated its ninth episode to feature ATM in "The Crystal Maiden: Belize and France," which evaluated the ghost stories behind the "Mysterious Maiden."

While there are several skeletal remains (reportedly from 14 individuals -- seven adults and seven children under the age of five) within the main chamber, the best-known is the aforementioned "'Crystal Maiden,' the skeleton of a teenage girl, possibly a sacrifice victim, whose bones have been calcified to a sparkling, crystallized appearance."

My guide Elias, who has been giving tours of ATM for over a decade, won me over with his captivating storytelling and depiction of these ancient Mayan times. He pointed out that with more research, "The Crystal Maiden" may not be a maiden after all, but a male -- but I guess I'll leave it up to the experts to decide.

Nevertheless, I was entranced by my journey and realized that ATM was a nice tie-in to my recent reporting on Jorge Guitierrez and Guillermo del Toro's "The Book of Life," an animated Day of the Dead-inspired visual masterpiece from 20th Century Fox and Reel FX Animation Studios.

"The Book of Life" ventures off to three fantastical worlds: The Land of the Living, the Remembered and the Forgotten -- little did I know that I, too, would find myself taking my own journey to the Mayan Underworld in Belize (and later to Tikal in Guatemala).

In "The Book of Life," which hits theaters Oct. 17, "Xibalba" plays a big part in the Mexican, Day of the Dead-folk art-enriched film. Manolo (voiced by Diego Luna) and Joaquin (voiced by Channing Tatum) both vie for the attention of Maria (voiced by Zoe Saldana). The leaders of the Underworlds, the Land of the Remembered and the Land of the Forgotten, Xibalba (voiced by Ron Perlman) and La Muerte (voiced Kate del Castillo) place a wager on who will win Maria's heart.

From the big screen to the depths of the ancient Mayan Underworld, I was among many Americans who are drawn to this Belizean gem -- there are reportedly close to one million tourists who visit Belize annually, 70 percent of whom are North Americans.

With an influx of tourists and a country that's home to 1,000 Mayan ruins that are scattered throughout the country, some artifacts have been compromised, however. In late May 2012, a tourist accidentally dropped a camera and fractured a human skull estimated at over 1,000 years old -- I learned of this quickly as my tour guide shared the news and his disdain.

As a result, no cameras are allowed in ATM. In order to protect the sacred grounds as you venure further into the caves, you have to remove your shoes and wear socks when reaching the upper dry chamber. In an effort to further protect ATM, the Belize Tourism Board, in coordination with the Belize National Institute of Culture and History, Institute of Archaeology, only granted licenses to a small group of agents to conduct tours in the cave.

What I loved about ATM was that the fact that they don't want to exploit the sacred Mayan grounds by allowing too many vistors in at once; they don't add lighting and walkways; and they don't have a gift shop or any intentions to have one. Thank the Mayan Gods!

ATM is an authentic experience and an incredible journey to the Mayan Underworld that I will never forget. I'm sure the Mayan Gods appreciate that the Belizians are trying to respect their stomping grounds, and if they don't... Well, who knows what could happen!

Check out a video on the Actun Tunichil Muknal (Cave of the Crystal Sepulchre), or ATM in the beautiful Central American country of Belize.