Salar de Uyuni, amid the Andes in southwest Bolivia, is the world’s largest salt flat. It’s the legacy of a prehistoric lake that went dry, leaving behind a desert-like nearly 11,000-sq.-km. landscape of bright-white salt, rock formations, and cacti-studded islands. Its otherworldly expanse can be observed from central Incahuasi Island. Though wildlife is rare in this unique ecosystem, it harbors many pink flamingos.