"It is amazing how much the look of these sand dunes has changed since the last time I was here a few weeks ago," said Eti, the guide from Geographical Tours.

I have no idea how huge dunes such as the Big Red in the Simpson Desert can change but one thing is clear - - it is tall, wide and made of the finest sand. Crossing it presents a real challenge for the vehicles and their drivers.

In addition to the 2.5 ton weight of each vehicle some of them are loaded down with hundreds of kilograms of equipment. But the expedition, as hard and tough as it is, must continue.

The bright yellow vehicles are lined up and ready to roll after a little air has been let out of the tires to make them softer and cope better on the dune. But crossing this area will be mostly down to holding onto the steering wheel and hoping for the best.

Each driver is on their own to make the crossing a success, but there is help. Itzik Mini has taken part in every Isuzu Challenge to date and is in charge of all the technical and 4x4 aspects of this expedition. He is as an expert 4x4 driver and has, in previous treks, overcome many of the problems we now face. We want to believe him when he says, in a cool calm voice, "we can all make it across the dune."

Between us we have fun bets on whom will make the best job of driving across the dune: the men or the women.

Standing at the edge of the dune, Itzik directs each driver - one by one - on the best route across. The lucky ones, who get stuck along the way, enjoy being rescued with the Warn winches that make easy work of a tough job. But as each car makes the crossing it is difficult to hear Itzik's advice over the loud applause and cheering.

"For me, the real issue is not if the vehicles are able to cross the sand dune," says Itzik, "what impresses me every time is the way people work together as a team to complete this difficult task. Every person who has completed it will never in their life forget the experience."

A few minutes later when the vehicles have all crossed Itzik not only receives more loud applause from all the participants, but is thrown over one of their shoulders and paraded around like hero.

We continue toward Birdswill - a small town on the eastern edge of the Simpson Desert that has a population of 120 people. However, after four days in the lonely desert, these people are seen as civilization.

And finally - a gas station. For the past four days we have been pouring petrol into our tanks from containers stored on the roofs of our vehicles, but today we see a proper gas station finally. So no need for our containers . Well, not today anyway.

Photographer : Gerry Avramovich