Salar de Uyuni (in Bolivia). But before that, you have to visit the Valley of the Moon. One of the driest places on Earth. It`s only for a trip and you see everything. They say it's the same as the bottom of the ocean. NASA is testing here its vehicles and you can see here lots of stars.
Quick Tips: If you come from Salta, Argentina, don`t bring your coca leaves. And don`t do trips in Salta(!), it`s nothing in comparison with this place.
Best Way To Get Around: Inside the town, just walk. To get outside the village, you have a lot of options. Mountain biking, buses, collectivos, horses, and walking.