Why is the lake in Bolivia salty?

The lake in Bolivia, primarily referring to Salar de Uyuni, is salty due to the evaporation of water that leaves behind high concentrations of minerals, including sodium chloride (table salt). This process occurs in a closed basin where water from rivers and rainfall accumulates but does not flow out, leading to the buildup of salts as the water evaporates. Additionally, the region's geology contributes to the saltiness, as it is rich in mineral deposits.