The Rio Celeste (or Celeste River in English) is a body of water located in Tenorio Volcano National Park, Costa Rica. Although many people erroneously believe that the Celeste River’s turquoise coloring is due to chemical contamination, it is actually the result of a natural phenomenon known as Mie scattering, caused by the individual components of the Celeste River’s two main tributaries mixing together to give the river its unique hue.

(Artist | Source)

costa rica / volcano tenorio by Jörn Schiemann on Flickr. Source - (http://flic.kr/p/b9eey8) rio celeste
Tenorio Volcano National Park (Spanish: Parque Nacional Volcán Tenorio) is a National Park in the northern part of Costa Rica, which forms part of the Arenal Tilaran Conservation Area. Tenorio Volcano consists of four volcanic peaks and two craters. One of the craters is sometimes referred to as the Montezuma Volcano.[1] Tenorio attains a maximum height of 6,287 feet (1,913 m). The awe-inspiring Rio Celeste (Light Blue River) is turned literally blue due to the emanation of sulfur from the volcano and precipitation of calcium carbonate. Thermal springs and small geysers dot the area as do rivers, waterfalls, lagoons and panoramic views. The upper area of the park is dominated by primary cloud forest, while the lower regions are carpeted with rain forest.