TELLURIDE — My knees are clacking like castanets, and if you look into my eyeballs, I’m pretty sure you’ll see rotating black spirals.

Somehow, and I’m really not sure how this happened, I’m clinging to a pair of metal rungs driven into a cliff wall in the valley high above the mountain town of Telluride.

In front of me, Josh Butson, owner of San Juan Outdoor Adventures, is saying something soothing, but I can’t make out the words. Behind me, Tom Watkinson, a member of the Telluride Town Council, is grinning and doing a one-handed hang while his tongue dangles out the side of his mouth like a hound dog.

I pause. I breathe deeply. And then I rally.

This stretch of the Telluride Via Ferrata, Butson tells me in a low, steady voice that’s designed to keep me from panicking, is known as the Main Event. It’s the most vertigo-inducing stretch of a cabled hiking and climbing route that takes visitors on a 2-mile bird’s-eye trip through the mountains.

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Beneath me, a sheer slab of rock plunges 330 feet straight down before it hits a gentler slope suitable for rolling another 200 feet or so. The view, if you’ve got the nerve to take it in, is spectacular. They tell me you can see all the way to Bridal Veil Falls, at 365 feet the tallest free-falling waterfall in Colorado, on one side, and down to the checkerboard of small-town streets in Telluride on the other.

All I see is the gritty gray rock a few inches from my nose, the cable that’s keeping me here, and a series of U-shaped metal rungs that serve as hand- and foot-holds.

Soldiers used via ferratas ("iron paths" in Italian) to cross the rugged Alps during World War I. Today they’re increasingly popular, especially in Europe, as a recreational pastime for adrenaline-seekers who want to pump up the hiking experience a few notches by donning a harness and clipping into safety lines stretched across ledges, sheer walls and narrow pathways.

Telluride gets credit for opening the first Via Ferrata in North America. Today, similar routes operate in Jackson Hole, Wyoming; the Royal Gorge in Canon City, Colo.; Mammoth Mountain, Calif.; and Banff, Alberta.

Credit the increasing number of routes to the Ski Area Recreational Enhancement Opportunity Act of 2011, which allows ski areas operating on Forest Service-managed lands to submit plans for summer attractions.

Telluride can thank a local rock climber named Chuck Kroger, who ran his own construction company, for its Via Ferrata, or Krogeratta, as some call it. He’d climbed extensively in the mountains around Telluride, and friends say he always wondered about the possibility of putting in a system here. Under cover of darkness, he anonymously began installing ladder rungs and creating a route in the early 2000s. He died of cancer not long after it was completed.

"He did it under the radar, at night," says Butson, who knew Kroger.

The underground route went mainstream in 2011, when the U.S. Forest Service granted it an official permit. But even now there is no admission fee or entrance gate. Anyone with the proper equipment can access the spot, which features dangerous drop-offs galore.

Outfitters like San Juan Outdoor Adventures offer a guided service and provide gear, knowledge and moral support. (Customers must be capable and at least 12 years old.) They also work to raise money to maintain the route and make sure it’s safe. I stayed at the Hotel Telluride, which offers a package deal that includes a trip on the Via Ferrata.

The company is taking precautions in the wake of the COVID-19 pandemic to keep clients safe.

"We’ve got protocols in place to mitigate risk," Butson told me when I checked with him earlier this month. All trips are small, private groups; clients provide their own transportation to trailheads; and climbers must wash their hands, maintain more distance and wear masks when they’re close to guides.

The route itself includes both cabled and uncabled stretches. Some of the uncabled parts felt just as scary as the cabled spans, because they offered no safety net.

My advice? Just don’t look down.

"Anybody not completely terrified of heights can pretty much do it," Butson says.

And even a few who are, apparently.

I once handed my backpack to my husband and belly crawled several hundred feet down an exposed trail at Glacier National Park, pausing periodically to curl into the fetal position and moan because I was so freaked out by the potential for disaster.

But Butson coached me well, showing me before we even started how to clip and reclip my harness line onto a cable and making sure I placed every foot carefully as I walked.

His No. 1 tip? Keep moving.

I did that, too, and as the minutes ticked past, I felt more and more confident. It took us about two hours to finish, and by then I felt capable of leaping tall buildings in a single bound.

As long as I had a safety harness buckled on, that is.