Salar de Uyuni salt flats in Bolivia (© Abstract Aerial Art/Getty Images)

Salar de Uyuni in Bolivia doesn't ease you in—it erupts into view like a horizon made of light. It's the world's largest salt flat, stretching across roughly 10,360 square kilometres at nearly 3,660 metres above sea level. The landscape dramatically shifts with the seasons: when the rain arrives, the surface floods just enough to become an enormous mirror, so perfectly reflective that sky and ground melt into a single glowing plane.