Bridge is ultimate Olympic high

For the ultimate Olympic high, try climbing the Sydney Harbour Bridge.

This is altitude with attitude, clambering over catwalks, ladders and arches to get a spectacular 360 degree view of one of the world's greatest harbours.

It is the perfect cure for anyone with a lifelong fear of heights -- clipped to the railing with a safety harness, you climb onward and upward to the crest of this great engineering feat 130 metres (426 feet) above the harbour.

Decked out in their Star Trek jump suits, the intrepid climbers grin from ear to ear at the summit. Exhilaration abounds. They pump the air with excitement for the group photo with their climb leader.

The ascent certainly provokes a real rush of blood to the head -- and the heart.

"We have had several couples proposing marriage on the bridge. The adrenalin gets pumping and they pop the question. No one has been turned down yet," said climb leader David Baker, always ready with his digital camera to capture the magic moment.

There was no shortage of volunteers among the guides offering to take actress Nicole Kidman up for the climb of her life.

One of the most poignant Bridge stars was a woman who celebrated her 100th birthday by climbing the bridge. She died the next year on her 101st birthday.

"I had a man doing the climb at the age of 90. He promised to be back in 10 years time," Baker said.

For, in every sense of the word, this is life on the edge. Come rain, wind or shine, the tours go ahead. Every kind of weather buffets you up there on the top of the world.

But climbs are stopped in electrical storms. They also called a halt when 50 knot gusts hit Sydney in the run up to the Olympics and caused travel chaos with fallen overhead train wires.

Safety is paramount on the slickly packaged three-hour tour. It begins in the hangar-like reception where visitors are briefed and, for what is already a very sobering prospect, breathalysed.

Empty your pockets, take off all watches and bracelets to avoid them getting caught on the rails as you climb.

Clip on sunhat, sunglass cord and rain hat if the elements are going to turn against you. No cameras are allowed in case you inadvertently bombard the traffic below.

First comes a quick rehearsal on the bridge mock-up before you step out onto the lower reaches of the bridge. That is the worst part. Don't look down. Eyes straight ahead.

Baker, a 23-year-old Sydneysider who delivers his running commentary on the bridge's history with flair and panache, can spot fear at 50 paces. Lock eyes on him, think of that 100-year-old climber and keep walking.

But what happens if a climber freaks out? "We get about one or two a week who opt out," Baker said.

"The first time I had a good look down," Baker said. "As soon as I stepped out on the bridge, I knew this was the job I wanted to do. It really has woken me up to the beauty of this city."

For the view is truly spectacular and you realise what a staggering piece of construction work it was to create this 52,800 tonne marvel with an amazing six million rivets.

"Only 16 people died in the construction. That compares to more than 150 building the Golden Gate Bridge in San Francisco," Baker said of this enduring Thirties icon Sydneysiders have affectionately nicknamed The Coathanger.