Caño Cristales is a Colombian river

Caño Cristales is a Colombian river located in the Serrania de la Macarena province of Meta. The river is commonly called "The River of Five Colors" or "The Liquid Rainbow", and is even referred to as the most beautiful river in the world due to its striking colors. The bed of river in the end of July - November is colored in gaudy colors, including yellow, green, blue, black, and especially red, the last caused by the Macarenia clavigera (Podostemaceae) on the bottom of the river.

http://www.rsvlts.com/2013/12/18/appreciate-earth-2013/the-river-of-five-colors-cano-cristales-colombia/