BUCKET LIST!
Twin rivers escape from springs underneath the Tenorio Volcano, their clear waters twist away down the valley through the Tenorio National Park. As the rivers merge, their waters churn into a fluorescent blue; a chemical reaction caused by the crystallization of copper sulfate, colloidal silica and sulfur.

The celestial waters flow through the rainforest, complimenting the emerald greens of the forest flora on their way to the blue lagoon; where the waters laze in a giant, azure pool devoid of life save for the tall, green grass-like weeds growing in the shallows.

Farther down, the river builds momentum joining with other rivers before flowing over the edge of a 100-foot waterfall in a spectacular cerulean shower. Visitors looking to enjoy the magic of the falls and the Celeste River will need to follow a trail a mile deep into the Tenorio National Park; located about two hours north of Arenal.

https://www.costarica.com/attractions/celeste-river-waterfall