Uyuni

Uyuni needs 2 days, almost entirely dedicated to the Salar de Uyuni, the world's largest salt flat. December-April (rainy season) covers the flat with a thin layer of water creating the famous mirror effect; May-November brings the dry salt flat, ideal for forced-perspective photos. It's inexpensive by international standards, though multi-day tours add lodging and food costs. Its salt flat, with over 10,000 km² of nearly perfectly flat salt, is visible from space and holds over half of the world's lithium reserves.