Hey, John Budd here, I'm currently in Potosi, the worlds highest city at 4080m. It's cold. Potosi used to be the biggest city in South America due to the silver mines but alas no more. However, i did go on a tour of one of the mines today and it was an amazing experience, especially hearing from the miners - one minor miner that we spoke to was only 17 and he had already been working there for 5 years! We were only down in the mines for a couple of hours but i was seriously ready for some fresh air and a shower by the end of it, tough conditions and the mine we visited was apparently one of the safer, cleaner mines. Off to Uyuni tomorrow morning, jb x