The Salt Mines of Uyuni, Bolivia (20/20)

One of the most mesmerizing underground attractions in South America, the Uyuni Salt Flats are home to vast salt mines that stretch beneath the ground. Beneath the surface of the Uyuni desert lies a network of salt mines that have been used for centuries, along with a complex system of caves and tunnels. The scale and beauty of this underground world are awe-inspiring.