The Cascadas de Agua Azul (Spanish for “Blue Water waterfall”) are a series of waterfalls found on the Xanil River in the southern Mexican state of Chiapas.
Wikipedia
These waterfalls consists of many cataracts following one after another, taken from near the top of the sequence of cascades. The water has a high content of calcium carbonate and other minerals, and where it falls on rocks or fallen trees, it encases them in a thick shell-like coating of limestone.
When light travels through water, it absorbs the entire color spectrum except blue, which reaches the bottom and is reflected back to the surface, resulting in beautiful shades of turquoise.
Wikipedia
The area was designated a flora and fauna protection area in 2000 by the Mexican government. The protected area covers 25.8 km2.