I did a 3-day-2-night excursion with Huracan tours (located to the right of the Todo Turismo office), and it was one of the best experiences I've had. I had seen a few photos of the lagoons and mountains before heading there, but they do not do justice to scenery there which was simply awe-inspiring.
One important factor is that this region is not frequented by too many tourists, so you often find that there is no sign of any human being or anything that is human-made. Even the spots which draw tourists (the geysers and fumaroles, the Stone Tree) do not have any barriers or guards around them lending an unspoiled view of nature.
And the vistas are simply incredible. In spite of the cold and the biting wind, I would often find myself gazing at my surroundings for several minutes. I found it hard to reconcile the bright blue (also red and green) waters of the lagoons with the arid land and the snow-capped mountains. The shapes and colours of the mountains were also unique and quite picturesque. For me, the Eduardo Avaroa National reserve had more appeal than the Salar de Uyuni.
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