SYDNEY, Australia >> The view over Sydney’s harbor is postcard-perfect.

Long blue fingers of water reach into the metropolis, creating peaceful mini-harbors cluttered with sailing ships.

Yellow ferries and gleaming yachts crisscross the harbor, surrounded by a city of cliffs, palms, evergreens and, beyond, the famous beaches of Bondi and Manly.

The Opera House, ceramic sails unfurled, sits at the heart — an architectural marvel and a survivor of cost overruns and political backbiting that now, half a century later, is Sydney’s Eiffel Tower.

Soaring above it all is a steel arch bridge, the largest and widest of its kind in the world, carrying traffic in eight lanes, trains in two and joggers and cyclists in two others.

It also is a span that sets hearts pounding.

Two decades ago, a member of the Young Presidents’ Organization decided to escort visiting company chiefs on a climb to the top of that bridge to take in the best view in Sydney. He turned it into a business, and more than 3 million people have made the climb, day and night, summer and winter.

It is — perversely, some might say — described not only as an adventure for people willing to pay more than $200, but also as a cure for what ails you, if what ails you is a fear of heights.

The highest point is 440 feet, or 44 stories, above the water. They haven’t lost a single climber, the people of Bridge Climb Sydney (bridgeclimb.com) like to say. But, as with so many marketing pitches, that isn’t the whole story.

I admit to some nervousness as two friends and I approached our appointment for a climb earlier this year. We had chosen the “twilight climb,” beginning just before 6 p.m. We had spent the previous two days exploring Sydney — taking a ferry to Manly and walking along scenic Bondi Beach and those nearby, beloved by surfers.

My traveling companions were friends from Los Angeles. We have been taking short vacations together for two decades, stealing time from busy work schedules with short jet-lag-be-damned trips to faraway locales. Machu Picchu in Peru was our first adventure, followed by Iguazu Falls in South America among locales.

The Bridge Climb was my friend Rich’s idea. I don’t like heights, but I agreed to go along.

As we roamed the city taking photos in the days leading to our climb, the bridge was a constant backdrop, streams of climbers visible from miles away.

When the evening of the climb arrived, we checked in at the southern end of the bridge. Each climbing group is limited to 12, with a guide. We began by filling out legal release forms, not exactly confidence-inspiring, but a feature of our modern world. We also blew into a breathalyzer. No one can summit with an alcohol level of .05 percent or more — a little more than half of what it takes to put you on the wrong side of the law when driving in California.

Adam, our guide, and his helpers stripped us of all of our earthly possessions — sunglasses, watches, hats, money, billfolds, iPhones. (One climber got to keep his hearing aids.)

We changed into blue Star Trek-like jumpsuits and were outfitted with harnesses and a circular plastic device to hook to the guy wires on the bridge. We put on headlamps and tied handkerchiefs around our wrists to ward off flop sweat. We climbed sets of steep steel stairs indoors to get a feel for what we were about to face. Finally, we were each given a wireless headset so we could hear our leader on the bridge.

An hour had passed by the time our band emerged onto long, narrow wooden planks — already 30 feet or so above street level — and started our march on the span, beginning with a walk along a catwalk above the passing traffic.

Adam, a former policeman, told us about the bridge and the landmarks visible across the harbor. “Only” six workers had died falling into the water during construction in the 1920s and early ’30s, he said. That didn’t provide much comfort.

We eventually arrived at the spot over the water where the bridge begins its upward arch. We climbed four steep ladders, about 25 rungs in all, to reach the starting point for the stairway that would take us to the summit.

At the top of the stairs, Adam turned to me: “You OK, mate?”

As if. I asked: “Does anyone ever turn back?”

“All the time,” he said. “At this point in the climb, I’ve had them crying in a puddle on the stairs.” That’s why, he added, other guides are stationed at the top of the stairs to take the less-than-happy folks back down. But, he added, “You look all right to me, mate.”

I imagined the scene — an able- bodied adult begging to be taken back to terra firma. Somehow, that didn’t seem right. So on I went.

As we climbed the arch step by step to the top, I tried to recall the instructions I’d read online: Don’t look down (not easy, of course, because you have to look at your feet on the stairs) and breathe. I found myself holding my breath anyway and began thinking, “Is this supposed to be fun?”

But I kept climbing, hooked to the steel guy wire by a piece of plastic that I doubted would support my weight if I ended up dangling over the water.

My friends Rich and Steve, oblivious to the danger, chattered with Adam about how high we were, and the guide kept pointing out sights in the water — way down below.

At the summit, underneath giant Australian flags unfurled in a 20 mph wind, the view across the harbor was captivating. A seaplane passed just 50 feet overhead. Birds flew well below us. We could see the beaches beyond the harbor and planes taking off from the airport 8 miles away.

We turned left to walk across the top of the bridge, pausing to watch the giant orange sun make a stunning 10-minute plunge beneath the water. The twinkle of Sydney’s tall buildings grew brighter, the skyline as majestic as Hong Kong’s.

After reaching the lower level, we again walked along a catwalk with clear views of the passing traffic below on one side and water — lots of water — on the other. My main thought was that this would be much less stressful with about .05 percent alcohol in my body.

We were finally back, about three hours after we had arrived at headquarters. The Bridge Climb people like to talk about all the folks who conquer their fear of heights on the journey. I suppose it’s true.

Fear of heights is a funny thing. Some experience it on a rocky outcropping over the ocean, some in an airplane and some climbing on a steel girder vibrating from rush-hour traffic below. I get it when I’m on my roof at home.

Is the Bridge Climb a cure for a lifelong fear of heights? Perhaps. But I’m not sure I’d do it again — and I’m definitely no more eager to climb onto the roof.