I'm about to experience one of the "must dos" here in Sydney, Australia - the BridgeClimb.

Starting at a whopping $180, it's a little steep, in more ways than one. But I heard it's worth it and doubt I will be climbing many more bridges in my life. If you want to climb at sunset, you have to pay nearly $100 more.

The Sydney Harbour Bridge was built in 1932 and is the world's largest, but not the longest, steel-arch bridge, with the top of the bridge standing almost 440 feet above the harbor. Fondly known by the locals as the "Coat Hanger," the Sydney Harbour Bridge just celebrated its 75th birthday. When the bridge opened, it cost a horse and rider three pence and a car six pence to cross. Now, horses are not allowed to cross, but you can bicycle or walk across the bridge for free. Cars pay about $3.30 for a southbound trip, while it is free to go northbound. In 1932, the average annual daily traffic was around 11,000; now it's 160,000 vehicles per day.

The whole climb ran like a well-oiled machine. One of the first things they do is a Breathalyzer test. Alcohol readings over 0.05 will exclude you from the climb. Yeah, I'm thinking you do not want to be stumbling onto the top of a 440-foot bridge.

The climbing crew herded 12 of us from room to room, gathering our specially made bridge-climbing suits, harnesses, headphones and radios, and clipping on accessories such as rain shells, handkerchiefs, and fleeces (in case it gets cold at the summit). After a small demonstration of what we needed to do on the bridge, we were on our way.

The whole experience lasts three hours. It's a surprisingly gentle walk, and perfectly safe, as long as you don't have a problem with heights. Most of the areas we scampered across were formerly accessible only to bridge workers. We went up several ladders, then climbed stairs up the eastern arch. In minutes, we were walking on the top of the bridge.

Halfway into the tour it started to rain, so we donned our special rain gear. Between the raindrops, we had amazing 360-degree views of the harbor and the stunning Sydney skyline. Looking down, I saw rush-hour commuters whizzing by to get home. Every few minutes, the bridge would rumble with the sound of the commuter train that crossed it.

Since we weren't allowed to bring cameras, our guide snapped some photos, which we could later buy at $15 a pop. Then we crossed over the top of the bridge and began our descent on the western arch. As on the way up, we were just walking steps; it was not as though we were scaling or rappelling on the side of the bridge. It was all very tame, but cool just the same.

Maybe this is something we can think about for the Benjamin Franklin Bridge - or maybe not.