It's not a cheap attraction, but the payoff comes in dazzling perspectives, writes David Whitley.
BRIDGECLIMB, SYDNEY
As a travel writer based in Britain and specialising in Australia, there is no single Australian experience that I'm asked about more than the BridgeClimb in Sydney. 
That's a pretty effective measure of global brand recognition.
However, the query usually runs along the lines of, "It seems incredibly expensive. Is it worth it?" To which my answer is usually along the lines of, "Well, it is undoubtedly overpriced, but despite that and despite there being so many other good things to do for much less, yes, it is worth it."
Seeing people in grey romper suits clambering over the Sydney Harbour Bridge is now such a part of the city's fabric that it's easy to forget how revolutionary it was when it opened in 1998.
Founder Paul Cave - whose father-in-law bought the first ever ticket for a train crossing of the bridge in 1932 - had the idea nine years earlier. Getting the concept right, the logistics and systems in place, and the permissions granted took almost a decade.
Given that effort, you can perhaps forgive BridgeClimb for being such a ruthlessly milked experience. It's a super-slick operation, with groups being processed and taken through the basics at precision-timed intervals. But the nagging feel of being factory farmed doesn't matter all that much once out on the bridge. It's more of a walk than a climb, toddling along the arc once a few initial steep steps are out of the way.
Fear of heights disappears fairly quickly, too - you're permanently clipped to a fixed cable running the entire length of the route and there are few gulp-worthy moments of looking directly down.
Wisely, the magnificence of the bridge and the harbour are allowed to take centre stage.
The perspective on the great handiworks of both man and nature is deliciously dazzling - especially from right at the top.
Once seen, any doubts of the BridgeClimb being worth it are expelled.
See bridgeclimb.com.