BOLIVIA // Imagine this: you're standing in the middle of the sky. Clouds above. Clouds below. Blue, blue, blue all around. That's what it's like at Salar de Uyuni, the world's biggest salt lake, after rain. The thin layer of water turns the utterly flat salt surface into a vast mirror. The horizon disappears and you seem to float. That's only one of the brain-bending experiences you'll have visiting these 10,582 sq km (4085 sq miles) of salt, high in the Bolivian altiplano. When the lake's dry, the white cracked immensity feels like something from Mad Max - a desolate, sun-scorched post-apocalyptic landscape. In the dry season you can visit the lake's two islands - Isla Incahuasi and Isla del Pescado. Both are craggy husks of land sprouting with cacti (and, increasingly, selfie- taking visitors). See too the geyser fields, hellscapes of boiling mud and sulphur steam. Several of the eerie high-altitude lakes, turned lurid aquamarine from high mineral content, are home to flocks of flamingos. Train your camera on herds of vicuña (a non- domesticated relative of the llama) and the occasional lone culpeo (a type of fox). At the edge of the lake, the settlement of Colchani is a centre of salt mining, producing some 20,000 tons per year. The place to sleep is the Palacio de Sal, made, obviously, of salt. Walls, floor, ceilings and furniture are made from more than a million blocks of salt - no licking allowed (seriously, that's a rule). When you finally return to civilisation after several days on the Salar, you'll feel as discombobulated as an astronaut coming home from Mars.

What is special about Salar de Uyuni?