Day 4 was really the first main stop of the tour. We spent the day at Coober Pedy, which is where ninety-five percent of the worlds opals are mined. The place is quite extraordinary - since the temperature can get as high as 110 degrees in the summer and below zero in the winter, the occupants have quite simply chosen to live under the ground where the climate doesn't affect them and it remains a constant 28 degrees. Today, apparently, it has been somewhere in the region of 100 degrees, and our coach captain, in an outburst of "telling it how it is" common to Australians, tells us that he believes anyone choosing to live in Coober Pedy to be a total nutter. Most of the occupants have dug out their own homes underground from scratch, cutting down into the hard Gypsum rock, and have created hidden mansions beyond the reach of the sun. They have television and electricity, and water comes in through a pipeline from an underground river twenty-seven kilometres away and is refined on site to allow hot and cold running water. The actual cost of digging such a home out of the rock is similar to that of buying a home overground although, of course, most of us would be quite annoyed if we paid for a new house and turned up to find a pile of bricks and a sheet of instructions telling us how to put it together ourselves. You really can have nothing but admiration for these people. These mad, mad people.

We were taken on a tour of a local home, where the occupants were actually sitting in the living room watching television as we wandered through. From the outside, all we could see was the front door set into a mound of earth in the ground, but stepping inside is like crossing the threshold into another world. It's a little like living in a luxurious cave - the walls are hewn from the rock and lit by lamps set into carved out pillars. We entered the structure down a flight of steps, and to our right was a large living area which looked exactly like a normal living room except that the floor and walls were solid rock. Down the hall was a rock alcove containing a wine cupboard, and rough hewn stone steps led up in all directions to bedrooms of multicoloured Gypsum. Most surprisingly of all, we climbed a flight of steps at the back of the house and found ourselves standing on the edge of a full size underground swimming pool. This place was simply one of the most beautiful homes I've ever been in, and if it wasn't for the fact that it's miles from anywhere and that going outside is like stepping into a furnace, I couldn't imagine a more perfect place to live. Down the road was a complete underground church, with the altar and pews hewn out of rock. Coober Pedy has a school, a hospital with twenty beds but only one doctor, and a small street of shops. They now also have an open air cinema - and for those wishing to stay a while on the way North to Alice Springs, there is even a complete underground hotel where you can sleep, eat breakfast in the restaurant, browse the hotel shops, and drink in the bar without ever going above ground. Living here must be like living in an episode of "The Clangers".

I took a tour of a local mine (Something I didn't get to do in 1999 when I visited Mount Isa). Provided with hard hats and torches, our small band of travellers was led in single file down a narrow corridor which snaked its way through the rock until I couldn't even imagine how far down we were. The passageway opened up into a large cavern where we were shown opal deposits and were able to stumble about in semi-darkness feeling claustrophobic before emerging into an opal shop where we were shown a demonstration of cutting and polishing and invited to part with large amounts of cash.

Coober Pedy also has its surreal side, in case living underground isn't already surreal enough for you. There is a Golf course in the town but due to the obvious lack of grass the rules are slightly different. Each player has to carry around a square of Astroturf which they lay on the ground in order to have a grassy surface on which to place their ball for each stroke. They also have special balls which glow in the dark, so they can play at night when the temperature is bearable - so a game of Golf in Coober Pedy generally consists of going out at night with an illuminated ball and a square of grass and hitting the ball across a large area of jagged rocks in the hope that it won't be smashed to pieces after the first few strokes. Not surreal enough? Ok - try this one. At the top of the town is a tree - but no ordinary tree. The locals obviously missed the greenery of home so much that they wanted something to remind them what a tree looked like - so they've collected up all the scrap metal in town and welded one together. That's right; they've welded together a tree out of scrap metal. The sight of this would've probably had me rubbing my eyes in disbelief and thinking that the desert heat was getting to me, if it weren't for the fact that Australia is littered with these oddities - any road trip of the country, for example, will allow you to stop at a number of so-called "Big" things, a collection of nearly 150 roadside objects including "The Big Banana", "The Big Prawn" and "The Big Pineapple". This is Australia at its most surreal.

So why would anyone go to such lengths to live in Coober Pedy, a town which sits in the middle of the burning desert and makes every attempt to roast you alive just for stepping outside your front door? The answer is simple - everyone here lives in the hope that they will one day hit a major opal field and strike it rich overnight. People flock in from all over the world to buy a plot, build a house and start digging, and a select few will go away millionaires. The reality, however, is that it costs so much to live and mine here that you would need to strike it lucky virtually every day just to stay alive - but it's like a form of gambling to the locals, and they don't seem to be able to imagine living any other way. If anyone did strike it rich, my guess would be that they'd just stay on and look for more.

At the hotel in Marla that night, the first thing I did was guzzle down all the water I could find - again, this was provided for us, as the tap water was still too salty to drink. According to Mike when he addressed us over dinner, the next day we would be starting the tour proper - we'd be heading out to Uluru where we would be going on a walk for several kilometres through the mountains. Always assuming that we didn't chicken out at the last minute, Mike told us in no uncertain terms that we were all in imminent danger of dropping down dead from dehydration over the next few days with all the walking he had planned - so we were all instructed to take water bottles with us wherever we went and to try drink the equivalent of eight pints a day. I've heard people make this recommendation before, and have never been able to understand how people do it - I've never drunk that much water in my life, even counting the copious amounts tea and coffee I consume on a daily basis, and so far have not died from dehydration. That's one pint every three hours, and if you factor in eight hours sleep then it actually comes down to one pint every two hours. If I try to drink a pint of plain water at once I would make myself sick - so to achieve the eight pints without throwing up I would have to literally walk around all day drinking from a bottle of water, and who the hell is going to do that? You'd have no time to do anything else; you wouldn't get any work done because you'd be walking to the office water cooler all the time; and you'd have to walk everywhere with a rucksack on your back containing bottles of water. Sometimes, I think they make these things up as they go along, just to see if anyone is stupid enough to do it! I was under the impression that this was a holiday, but it seems that Mike obviously wants it to become some sort of endurance test.

One of the most pleasant things about the tour so far had been the community mealtime in the hotel at the end of each day. Particularly among the Canadians, there were some really funny people travelling with us, and the evening meal really was a time when we could all get together and unwind after an exhausting day, telling jokes and sharing anecdotes. There was one guy in particular, a policeman from Belgium by the name of Arno (the laughing policeman, we calledhim), who had us all in stitches - I actually saw people laugh so hard at something he'd said that they sprayed their drink out of their nose, and I only previously thought that happened on television.

We saw some Kangaroos for the first time during the evening, but unfortunately they were on the menu at dinner - which, frankly, made me feel a little sick. I didn't really know why - people of all nations eat the animals of their country, and Kangaroos aren't endangered in any way, but to a westerner of delicate palate, somehow the idea of eating one of those cute bouncing things you see on television saving small boys from wells didn't seem right and I passed.

"What's that skippy? Jimmy's fallen down the well? Who cares, I'm rich - I've found a flaming talking Kangaroo!"

From Coober Pedy, the AAT Kings tour continued on to Uluru and then through to Tennant Creek, Mataranka, Katherine Gorge and eventually Darwin. As I have already written about my visits to these places in some detail earlier in this book, we return now to my tour of Australia with Eloise in 2003 as we were arriving in the capital city of South Australia, Adelaide.

About Simon and Burfords Travels:

Simon Burford is a UK based travel writer. He will be re-publishing his travel blogs, chapters from his books and other miscellaneous rantings on these pages over the coming weeks and months, and the entry on this page may not necessarily reflect todays date.