Guanacaste, Costa Rica

Rio Celeste 

This river in Tenorio Volcano National Park is named for its turquoise color which comes from a chemical reaction between two of its tributaries.

• The Buenavista River contains a large amount of aluminosilicate nanoparticles.

• The Sour Creek has a below-normal pH

The reduction in pH causes aggregation of the aluminosilicate nanoparticles to about 540 nanometers in size that cause "Mie Scattering"

The shape of this frog's head and the black dots behind its eyes are intended to imitate a snake's head, thus warding off predators.