Laura Bly, hanging loose 1,168 feet above downtown Toronto.

I’m an adrenaline junkie. Always have been.

A front row seat on the word’s fastest and steepest wooden roller coaster? You bet. Hang-glding over the beaches of Rio? Check. Skydiving and communing with great white sharks in South Africa? No big deal. With all this under my belt, walking on a five-foot-wide railing around the outside of a tower 116 stories above Toronto shouldn’t rattle me a bit.

Or so I thought.

Now in its third season,the EdgeWalk at CN Tower offers thrill-seekers the ultimate sightseeing tour of Canada’s largest city from one of the world’s tallest free-standing structures. My first reaction: “Let’s do it!”

Once I’ve signed a voluminous waiver confirming, among other things, that I don’t have any broken bones and haven’t had surgery in the past six months, I climb into a prison-like, bright red jumpsuit and harness and lace up a pair of no-slip tennis shoes. So far, so good. But after removing all jewelry, being swabbed for explosives, and administered a breathalyzer test (good thing I’d nixed that mimosa), my bravado is as shallow as my rapidly increasing breaths.

Shuffling out to the platform on a dazzling spring day, I cling to my industrial-strength safety cable clipped to an overhead steel beam. And when, in typical Canadian fashion, our tour guide reminds us to be considerate and avoid spitting over the edge, I glance at one of my comrades and read his mind before he can say it: “My mouth is too dry for spit!”

We’ll be strolling at 1,168 feet atop the main pod’s 360 Restaurant – still about a football field below the tower’s SkyPod observation deck, but high enough to give this veteran skydiver the heebie jeebies. And I’m not alone: Many EdgeWalkers who’ve already stepped out of a perfectly good airplane at 10,000 feet say this experience is scarier, presumably because we have more time to contemplate our bravery…or folly.

With a bit of “you can do this” coaching, however, our band of six adventurers dutifully line up for a round of “toes over Toronto” and “butts over Toronto.” The safety briefings and seemingly endless equipment checks pay off; within a few minutes, our death grips ease and we’re so confident in our umbilical cords that we not only admire the bird’s eye view of a futuristic city hall but crack jokes about the mayor’s suspected dope smoking.

Then, as mist from Niagara Falls glints nearly 80 miles across Lake Ontario and planes swoop in for landings at the city airport below me, I lean over the edge and reach for the clouds. And, for a few glorious minutes, I really am “the king of the world.”

Toronto’s EdgeWalk attraction lets intrepid strollers walk around the circumference of the CN Tower’s 360 Restaurant, which towers 1,168 feet above the city. Photo: Laura Bly

Cool as a cucumber: Laura Bly takes a breather above Billy Bishop Toronto Airport.

Details:

The EdgeWalk experience, which lasts 90 minutes including walking time of about 20 to 30 minutes, runs May through October and costs $175 plus tax per person (I was a guest of the CN Tower). Participants must be 13 or older and weigh at least 75 pounds; the walks operate rain or shine, except during high winds or lightning storms.

Tempted, but worried you’ll lose your nerve once you step outside? Of more than 32,000 people who’ve signed up for the tour, I was told that only about a dozen have chickened out – perhaps because tickets (which include a video, two printed photos and re-entry to the tower) are nonrefundable.