I joined a group of 10 persons from different nationalities and we split into 2 4X4... According to the travel agent these 4X4 were from the 90s. This was probably true for the one I went in but the other one was more likely from the 80s or 70s :P. Still it worked. One after departing from SPA we crossed the Bolivian border at 4400m of altitude. Just some outpost in the middle of the mountains. And we started our tour around lakes, volcanos, geysers, sand, dust... As we kept climbing and climbing till 5100m many people in the cars started to have headaches but to my surprise I felt great... or at least good. Just before noon we went to take a bath in hot spring water.. it was nice and also an occasion to meet some french people doing a similar tour with another travel agency. Then we went to the hospedaje where we were going to spend the night... at 4350m of altitude. The evening was nice, chatting with other people having travelled a lot too around the world, then playing a french game called Loup Garou (seems to be known in UK too) and going to bed at 8pm :PPPP. The night was really difficult and I guess no one slept for more than 2 hours. On my side after trying to sleep for hours I started to have difficulties to breath and started to panic... I then decided to go outside (where it was minus something) and finally felt better. Afterwards I went back to bed under my 10 blankets cover (it was also minus somthing inside :S) and played PSP for some time before finally finding sleep for 1-2 hours. Second day was similar to the 1st one, seeing similar things... and ending up close to the Salar of Uyuni. The hospedaje was again very "rustic" with electricity for only a few hours in the evening... and hot water for just some minutes. On the third day we awoke at 5am to go see the sun rise on the salar of Uyuni... a huge flat place with salt everywhere, looking like sand... It was really magic. And after having a breakfast we started to take some stupid pictures like everyone does, playing with perspective (there is nothing expect for the flat salt which means you have no idea about the distances). Afterwards we spent a few minutes in a old train cemetary before finally reaching Uyuni in the afternoon. On my side I decided to take a nice bus to Sucre as there is nothing to do in Uyuni. But before I spent the afternoon drinking licuados and talking with my new friends from the trip.