Salar de Uyuni in Bolivia

© Theo Allofs/Minden Picture

Just a pinch. Salar de Uyuni, Bolivia

More than two miles above sea level, near the crest of the Andes mountain range in Bolivia, is an anomaly of the natural world - a salt flat bigger than some countries.

The Salar de Uyuni in Bolivia is the largest salt flat in the world at about 4,000 sq miles. It’s the remains of an ancient lake that evaporated long ago, leaving behind a thick mineral crust that is both a source of edible salt and an important breeding ground for flamingos. But for a battery-hungry world, the greatest riches might lie below the crust - a vast brine rich in lithium.