There's a subway underneath the Sydney Harbour Bridge between Observatory Hill and the Rocks.

It's probably about 100m long and has tiled walls on both sides.

And both walls, for their entire length, look like this...



So it's either concerted vandalism (which seems unlikely, as there are CCTV security cameras everywhere)...

...or art.

I think one of the ways you can get a handle on other cities is by their public transport. When you go somewhere new, you should always have a go!

For a start, if you're anywhere abroad, the chances are that your experience will be loads better than anything you could expect in Britain. In Britain, we can't really do public transport. It's dirty and slow and unreliable and crowded and the places where you get on and off are nowhere near anywhere you might get on anything else.

In Sydney, it's great. Everything links up, it's cheap, frequent and clean. You can use one ticket all week on the ferries, the buses and the trains.

And the trains are great! (Here is a lonely tourist not noticing one has arrived behind him...)



They are double decker!



We can't do this in Britain because the bridges and the tunnels weren't designed for double-decker trains and all the platforms would have to be altered - it's too late and would cost too much money now. If only someone had thought of double-decker trains to start with - we seem to be the only country (apart from Hong Kong) which has double-decker buses...

They also have five seats across rather than four which, by my maths, honed by a summer of currency conversion, means that each carriage can take two and half times as many passengers as a British train.

But if all this wasn't clever enough, they go underground too. You don't have to get off a train to get on a tube, the train becomes a tube by the simple expedient of going into a tunnel. (A very high, double-decker tunnel...)

And Circular Quay probably has one of the best views of any railway station...



But if you're commuting (easily and efficiently), you probably don't notice...

Although you can see the two most famous landmarks of Sydney really clearly from many different angles around the harbour, it's increasingly difficult to see either of them the further you move south into the CBD (Cental Business District, as City Centres are known over here...)

The Bridge gradually disappears between high-rise (and in some cases, quite low-rise) buildings...



...and the Sydney Tower, which boasts Sydney's Best Views, only manages to squeeze the Opera House in between a couple of skyscrapers...



But Mrs Macquarie had the right idea...

Mrs Macquarie was the wife of Major-General Lachlan Macquarie, Governor of New South Wales from 1810 to 1821. He has all sorts of things named after him, Lake Macquarie, Port Macquarie... even Mrs Macquarie. But she did well in Sydney with a point, a road and a chair.

The point is well visited because it has the standard postcard view of the disappearing icons...



Once you have this photo (or one like it with better, bluer skies), then your work is done and you can go home.



So it's a good job it's the last day really...

(There is a "me in front of..." shot - in fact, there are several... and a story...)

Lisa, our guide up the Sydney Harbour Bridge, was a laugh.

Standing at the top (that's not spoiling it, of course I made it to the top...), she told us how far it was down. 139 metres or 439 feet. "Or 5 seconds", she said "if you choose to go that way..."

Actually the whole Bridge Climb operation is utterly professional. Right down to its little yellow clips, which are the most important safety feature of the climb. They clip everything you might possibly have to take up with you to your fashionable grey boiler suit to avoid you dropping it onto the traffic 5 seconds below. When the guy setting up the climb proposed the idea to the council, who own the bridge, they gave him 96 reasons why it wouldn't be possible.

Like a true entrepreneur, he researched and solved all 96 points of objection and that's why you can climb the bridge today.

One of them was the dropping things. Glasses, hats, handkerchiefs, fleece, radio, headsets (with special bone induction headphones - you don't put them over your ears, they rest on your cheek bones)... the whole lot has to be clipped on for dear life.

Then they have to clip you onto the bridge and you practise this before you get out there on a bit of scaffolding'n'ladders they have rigged up in the reception building. It's done using a bloody clever bit of equipment actually - a little rotating mechanism of cogs and gubbins which means that you can't become detached from the high tension steel safety wire which follows you round the entire route.

A couple of bits are ladders and they show you safely how to get up and down them. When you are actually out on the bridge, she calmly tells you over the skull-vibrating headsets that the real ladders take you up between lanes 7 and 8 of the traffic. (And between two express train lines on the way down.) She's so reassuring though, that you don't worry.

Here's a photo I took later from one of the bridge towers, which show a little of the route you take... (You'll have to zoom in to see properly...)



You can't take your camera up on the real climb because you might drop it. I think they could find some ingenious way of yellow-clipping it to you so that you could, but then they wouldn't be able to overcharge you for the official photos they take... Of course I bought them - I'm probably never doing it again!





It's a real sense of achievement - you even get a certificate!

But your legs don't half ache afterwards...