This is high up on my list:: World's largest salt flat located at Salar de Uyuni, Bolivia. During the rainy season, the water turns into the world's largest mirror. It's called the border between heaven and earth.
Salar de Uyuni is the world's largest salt flat at square kilometers. It is located in the Potosí and Oruro departments in southwest Bolivia, near the crest of the Andes and is at an elevation of meters above mean sea level.
Salar de Uyuni is a magical place: When covered by water, the world's largest salt flat becomes a mirror, and anyone walking across it appears to be walking on clouds. The salt crust covers 10 583 square kilometres in southwestern Bolivia
Marble Caves of Patagonia in Chile – Lake Carrera. The lake is on the border of Argentina and Chile, and the caves are located on the side of Chile. The caves are the three main grotto: Chapel (La capillaries), Church (El Catedral) and Cave (Cueva).