So another first - we have now stayed in the highest City in the World - Potosi. At 4,800 metres (just under 16,000ft) this place does affect your breathing. A shade higher and bottled oxygen would be required. The citys primary purpose is to serve the nearby silver mones. Nothing more than a small town, it was founded in 1545 when a local Indian discovered silver in the nearby mountain. The story goes that when he was camping overnight in a cave he was cold and decided to light a fire. Unbeknown to him he had lit the fire over a seam of silver in the floor of the cave and after about an hour the silver began to melt. During the Spanish Conquests, Potosi was one of the richest in South America and now it's one of the poorest in Bolivia. We arrived yesterday and keen to make the most of our time here we took a trip to the Casa de Monero (literal translation, the house of money - the Royal Mint). During the Spanish colonisation of many countries in South America, Bolivia and Potosi specifically used to be one of the Spanish Royal Mints, producing coins and medallions, in fact anything the Spanish wanted making from the local silver. Cerro Rico (Rich Mountain), which overlooks the City was found to be rich in silver, as well as other minerals and precious metals. The Spanish exploited this to its full and in the space of a 100 year period removed 50,000 tons of silver from these mines, the products of which were all shipped back across the Atlantic to Spain. Of course, the locals were the source of labour and we were shocked to discover that since the mines were first discoverd in the late 16 Century nearly 8 million people have died as a result of working in them, either directly or through the (lung) diseases they inherited later. Whilst they used to be a nationalised industry they are now run as co-operatives. Today there are 37 co-operatives in with a total of 7,000 miners working 6 days a week. There is no such thing as a maximum working week here or a minimum wage. There are 3 levels of people in the co-ops - the lowest of which will earn the equivalent of $1000 per year working 6 days a week and sometimes 36 hour shifts - it made us appreciate the benefits of working behind a desk! Most miners last about 10-15 years before either one or both lungs give out from the silicosis or other gases ingested. There are no fancy extraction methods for noxoius gases here or any safety features such as masks. After they become too ill, the get a pension from the co-operative of about 14 pounds a month. To fund this each miner pays a percentage of his wages to the co-operative. About 1% goes towards the cost of coffins! To earn a little extra, the co-ops allow visitors into the mines during the working hours - so of course, it was essential that we took a look at first hand and this morning we took a trip into the Rosario mine, above the city of Potosi. The first stage is a visit to the miners market where we stock up on cocoa leaves and drinks which we will offer as gifts to the miners. Cocoa leaves are illegal but the miners chew them to release the cocaine like substance (cocaine is made from cocoa leaves) which helps them work longer and harder. In fact the Spanish conquestadors originally banned miners using cocoa leaves as it was unholy. But when mine production fell, it was given special approval to be used again, with the blessing of the church! Not only did we stock up on presents but we bought a bit of dynamite for our own entertainment. It's freely available in the market and at 50p a stick it seemed like a good idea! Kitted up in the sartorial elegance of red waterproof jacket and trousers, wellies and hardhat with lamp we started off into the tunnel that gradually had you walking at half your height for a good portion of the way - we particularly felt sorry for a guy who was about 6 feet 3inches, in our group! We quickly saw the necessity of the hard hats though as there were frequent squeals as heads hit the very low roof. The work was hard and it was all by hand, including the guys pulling the wagons by hand. However, push came to shove for Carol when the guide asked us to climb through a 20m passage that was no more than 3 feet high - nerves, dust and nasty gases (arsenic, cyanide and asbestos being the main ones) got the better of her and we decided to stay in the bigger tunnel and wait for the group. However, we reflected on this and decided that the tunnels were akin to Chris' ride on the mule in Peru - you hated it at the time but were glad you had done it at the end! The final piece of the mine tour was a visit to El Diablo (the Devil). The miners are very superstitious and believe is offerings to God or in this case because it is below the earth, to the Devil. They have a statue which the miners offer all manner of gifts to, including llama foetus, cigarettes, alcohol and cocoa leaves. Having had a couple of hours in the mine, the next thing on the agenda was to take our stick of dynamine and blow something up! The dynamite was mixed with amonium suplhate to give it an even bigger bang and the side of the mountain outside seemed as good a place as any to light it. No regulations, planning or advance notice required, we just light of stick of dynamite and run for cover. What a blast!!! Having now visited the main sites in Potosi we are back on our travels again tomorrow to Tupiza in the South, about 90km from the border with Argentina - where the salt flats and last known whereabouts of Butch Cassidy and the Sundance Kid await our adventures!