West Puerto Rico - I arrive at 5:45 am Sunday morning for my adventure in the 30-million-year-old Angeles Cave, part of west Puerto Rico's El Yunque in the Rio Camuy Cave system, the third-largest of its kind in the world.
In the jungle-painted adventure utility vehicle, a boom box playing the soundtrack to Raiders Of The Lost Arc blasts us out of our sleepy state. We're greeted by Aventuras Tierra Adentro adventure company owner/instructor Rossano Boscarino and assistant instructor Anibal Regis.
A video screen on the bus runs a tape of both of them running through instructions and safety procedures, while the driver adds wild jungle animal noises.
They demonstrate the importance of conservation, safety and equipment protocols in short skits that keep the 16 of us howling with laughter all the way to the cave.
After a quick drive through the forest, we don harnesses, headlamp-equipped helmets, safety jackets, gloves and backpacks stuffed with water and food.
We approach the cave via an exhilarating 76-metre zip line. Then there's a daunting but spectacular descent down a 100-metre vertical wall into the sinkhole mouth of the cave below.
Rays of sunlight coming through a window in the cave illuminate a small subtropical fern gully. I'm in paradise. As we penetrate its depths, we're awestruck by the cave's beauty. We run through near-shin-high mud and are mesmerized by large spiders and small scorpions.
Twenty metres up, toward the roof of the cave, are the homes of bats. Small igneous rock pools hold magnificent crystal-clear waters.
Our excitement mounts as we take the first of three cliff jumps into the river pools below. There is some danger, since the rainy season is approaching and there's a threat of flash floods. In these underground rivers, water levels can rise quickly. Logs and other debris can wash in, flooding the routes and ramming logs into stalactites and stalagmites.
The adventure continues through a roller coaster of slippery mudslides. Jagged white-tipped stalactites 100 metres high hang from the roof , and round or oval stalagmites push up from the ground.
Our guide, Boscarino, can't contain his incorrigible mischievousness. At one point he orders us to turn off our headlamps.
Several minutes pass. When we turn them on, he's 30 metres up in the cave, performing another of his skits, complete with music and props. For his finale, he runs down and jumps into a pool below.
Finally, we return to where we started, in the mud near the entrance. We're cold, wet and tired, and the sunlight filtering into the cavern is a welcome sight. We happily drag ourselves up the 100-metre hike back to our bus.
Curious about their qualifications, I learn that Aventuras Tierra Adentro's Boscarino and Regis hold SWIFT water rescue and search-and-rescue certificates. Boscarino is a master certified rock climbing and rappelling instructor.
The two of them have taken people on adventures since December 1987, appeared on MTV and trained U.S. Special Forces and movie stunt men.
Boscarino says one last goodbye as we leave the bus. "It's great to see perfect strangers come together and build a strong team who look out for each other and watch each other's backs."
He winks, winds up a fake furred pink pig and sets it down on the bus floor, where it wildly waves goodbye with its tail to the happy adventurers.