Arenal Ppreserve, Costa Rica - Deep in the tropical rain forest, I'm several steps behind Bernardo Perez, my Costa Rican guide, when I hear a growling sound behind me. As though a prehistoric beast were thundering through the brush, the ground begins to shake. I do a quick shoulder check. The coast's clear, but the volcano behind us does look a little menacing. Glancing behind me one last time, I put my misgivings aside and follow Perez deeper into the forest.
We're hiking Arenal Volcano, 120 kilometres northwest of Costa Rica's capital city of San José, so I have good reason to be worried. In a country with over 100 volcanoes, Arenal is not only the most active, but one of the world's most dangerous. A week earlier, a series of eruptions rocked the northern face of the volcano, spewing an avalanche of stone and gas that forced the evacuation of locals and tourists.
I'm not really a "lava junkie" (a volcano chaser), so why have I chosen the dangerous northern side for my hike? The attraction is a new 250-hectare nature preserve that features a 3-kilometre hike over a series of bridges, tunnels and trails through old-growth rain forest. Eight fixed bridges range in length from 8 to 22 metres and six suspension bridges between 48 and 98 metres.
The trails bring visitors close to some of the densest and most diversified forest in the world. Vegetation growing in the mineral-rich soil created over centuries of volcanic eruptions provides habitat for many species of animals and birds.
"A dart frog. Very poisonous." Perez points to a glossy red shape on a broad leaf. "And there. Do you hear that noise?" It sounds like a creaking door.
"It's a chestnut-mandibled toucan, the largest but not prettiest of the species." He indicates a large bird with an enormous yellow beak.
I duck as something flies straight for my hair - a crystal butterfly, its transparent wings outlined in blue like a cartoon character.
"Watch out," says Perez, pointing down. Leaf-cutting ants, in perfect formation, each carrying a brilliant emerald-green bit of leaf, wind across the trail.
With a full dance card of wildlife in Arenal Preserve, it's easy to forget that we're in the shadow of a volcano. The Guatuso Indians who once lived in the area believed the volcano was home to the god of fire, and regularly performed rituals to control their destiny.
The volcano was considered dormant until July 29, 1968, when it suddenly erupted, sending out shock waves, hot gases and rubble. By the time it settled, it had destroyed two villages and killed 78 people. The two new craters it spawned continue to belch ash and rock today.
Because the area is still considered a danger zone, several safety precautions are in place. A seismographic network issues warnings of impending eruptions, and the Smithsonian Institute has a monitoring station on the south side of the volcano. Evacuation routes are clearly marked.
The volcano's dark history adds some sobering thoughts to the final leg of our hike. I pause to admire a tiny hermit hummingbird pollinating a red shrimp flower.
"Stop! I smell monkey poop," Perez tells me as he points to the treetops.
Sure enough, dark shapes move about high in the canopy. Spider monkeys - a rare sighting compared to the more common howler monkey - dance through the trees, looking like large shadowy people, their long black arms stretching across the branches.
Then, like a giant clearing his throat, the volcano rumbles. The shrimp flower quivers.
Beauty and danger - an irresistible combination.