An amazingly good paved road led from Potosi city to Uyuni, a desolate, dusty and dirty town in the desert landscape of the high south western altiplano (3669 metres). The area is so flat that the wind, which is quite cold at night, whisks through the streets. No we haven't gone mad coming here as this is the jumping of spot for the Salar de Uyuni (world’s largest salt lake with an area of 10,582 square Kms).

We booked ourselves a two day tour and whilst we waited we visited Uyuni’s only tourist attraction, the train cemetery. This consists of a large collection of historic steam locomotives and rail cars rusting away just outside town. In their day they were used to transport ore from nearby mines. It was quite sad to see them like that. As you can imagine, Peter loved the train cemetery.

The Salar de Uyuni (forgive the following Geology lesson) is located near the crest of the Andes, at 3650 metres above sea level. Some 40,000 years ago, the area was part of a giant prehistoric lake. When the lake dried, it left behind two modern lakes and two salt deserts. The salt had leached into the lake from the surrounding mountains, where it had been deposited before the Andes had formed, when this part of Bolivia was beneath the ocean. The Salar is estimated to contain 10 billion tons of salt, packed between layers of sedimentary rock that extend to a depth of 120 metres. Around 25,000 tons is extracted annually (I will let you do the maths). In addition to salt the Salar has the world’s largest deposit of Lithium. Apparently international mining companies are dying to get their hands on it.

The trip started with a visit to the local salt factory. I use the word factory very loosely as it was just a small building (made of blocks of salt cut from the lake) where they warm the salt to dry it out before it is ground and bagged. The salt itself is dug up (with a shovel) from the lake and piled in the rear yard of the building. We brought two bags of salt, which in their homemade bags look suspiciously like drugs. It may prove interesting when we ship back home!

The lake itself is enormous .We drove for 3 hours to cross it. They warned us that we would need sunglasses as the glare from the white salt surface is very strong. (Note my new £2.70 sunglasses- cool, no?) Half way across we had to stop to take the obligatory silly photos. We had lunch on one of the 36 small islands (made of a mix of volcanic and sedimentary rocks) that sit in the lake. You would have thought they would be barren, but no, there were plants, giant 900 year old cacti, small birds and Bolivian rabbits (weird creatures with hairy ears and long hairy tails). We stayed the night in a hotel made from salt blocks, ate dinner at a salt table sitting on salt stools and slept in a salt bed. The only thing missing was salt at the evening meal, really! Next day we visited some nearby lakes and weird rock formations before returning to Uyuni. We did finally get to see the elusive and rare James Flamingo.

As we left Uyuni we popped onto the salt lake with Gerty. We did think of having a coffee but at this point the gas cylinder decided to run out. The drive to La Paz was initially on a very bumpy dusty road. It was so bad that for most of its 100 miles people had made new tracks beside the road. As these got rutted they made new ones further out, and so on. At some points we lost sight of the proper road completely and wondered where we would end up.

At a river crossing we came across a stuck and sinking Toyota people carrier. Gerty came to the rescue and pulled them out. It was a bit worrying stopping in the middle of this wide river and I kept watch while Peter got wet feet sorting out the tow line.

It took two days to reach La Paz so we had to camp by the road. With no gas and the temperature dropping to below zero Peter tried a Ray Mears type trick for cooking. It consisted of a tin can filled with sand soaked in diesel. Unluckily it didn’t work except for producing a lot of black smoke.

We reached La Paz the next lunchtime. The city sits in a narrow canyon at the edge of the altiplano. To get down to it you drive through El Alto the huge urban sprawl (which looks down on La Paz), with a population greater than La Paz, where a lot of residents have no access to electricity and water and the night temperatures are below freezing. The five lane road through El Alto was blocked with microbuses. We sat amongst them for half an hour before a kind driver advised us we were in the queue for the bus stops and let us cross into the lane going into the city. Even that was not the end as the city was heaving with microbuses and taxis all sounding their horns. In the end (just after Peter starting swearing at drivers-the first time ever) we asked a taxi to lead us to the hotel. After a couple of beers Peter had recovered. This was probably the most harrowing drive we have done, the taxi and microbus drivers are completely bonkers.

Gerty had developed a bit of a squeak during the drive from Uyuni, which considering the state of the road was not that surprising. On investigation, in the hotel garage Peter found that the exhaust heat shield had shifted and was hitting the chassis, so nothing too serious. Now bent out of the way. He then checked the oil levels and the rear axle oil decided to overflow all over the clean concrete floor of the hotel car park-oops.