Siena Yates becomes a 'Mayan underworld explorer'.
The most striking thing about the Mexican underworld is just how quiet it is.
You can hear dripping water a mile off, the scurry of a cave spider and your own breath sounds like a roar.
Piercing that silence is my guide, Pako. He's singing soft and low, a traditional song of his people, the Mexica tribe. I'm floating on my back under a ceiling of stalactites, in crystal-clear blue water while bats whoosh overhead.
If you're in Mexico looking for a magical moment, this is it.
The tour, one of Intrepid Travel's Urban Adventures, is billed as the "Mayan underworld explorer" — a caving excursion just out of Playa del Carmen.
It's not until you meet the local guide Pako that reason for the name becomes clear. A staunch protector of his cultural history, mythology and customs, Pako is also an activist for conservation and wildlife protection. He and a group of like-minded friends spend their spare time wandering the elaborate cave systems near PDC, attempting to map it all out and discover pieces of history along the way.
He's been exploring these caves since he was a child, so the two-hour tour he takes me on is childs play to him, but an adventure for a complete novice like me.
First, he drives me through the jungle, in which he says he regularly encounters jaguars and other wildlife. It's a spot only for locals — even if you could find it on your own, you have to be cleared to go in. As a result, it's largely untouched by the ever-reaching hands of tourism. It feels different out here.
After a quick briefing, Pako gears me up and leads me down a set of stairs to a cave mouth where the adventure begins; climbing over stalagmites, squeezing through spaces, swimming through tunnels and more.
As impressive as it all is, it's made even more special when you learn why it matters. I learn that the caves are seen as the underworld, and the journey into them represents a rebirth, of sorts. Pako explains how descending underground represents the end of life, the journey through the darkness — with all its hidden beauty — represents the afterlife, and the ascent back up to ground represents birth, as you literally emerge out of Mother Earth.
I won't say mine was a rebirth-type experience, but those metaphors did continue to pop into my mind as we explored; the fear and trepidation journeying into the unknown, the struggle to get acclimatised and then: paradise.
Pako led me to a massive cenote, a swimming hole which was like a magical, underground lake in which I was free to swim, dive and float in the crystal-clear water, illuminated by the multi-coloured solar-powered lights Pako and his mates have rigged.
That moment is one I will never forget, particularly as Pako shared some traditional Mexica songs with me, explaining their meanings and their importance in his culture.
After weeks of traipsing around Mexico, I felt like I'd seen one of its secrets.