Caño Cristales, located in the Serrania de la Macarena, a province of Meta, is a Colombian river with many rapids and waterfalls. In English language, Caño Cristales means, ‘Crystal Channel’. But, the river is popularly called the ‘River of Five Colours’ or the ‘Liquid Rainbow’, as during certain months of the year the river mesmerizes the viewers with its amazing display of colours. This unique natural wonder is often referred as the most beautiful river in the world, the river that ran away from paradise.

During most of the time in a year, Caño Cristales looks like any other river, without any distinguishing feature. The magical transformation happens only for a particular period, in between two particular seasons. Between the months of June and November, the otherwise normal river with transparent water, blossoms in a vibrant explosion of colours and becomes lively with sparkling yellow, blue, green, red and black hues.

The magician, responsible for the wonderful transformation, is a particular fussy endemic aquatic plant growing on the river bed, known as ‘Macarenia Clavigera’, which is as delicate as a velvet lace and clings to the underwater hard surfaces. The said plant, known as Podostemaceae, or Macarenia clavigera requires just precise conditions of the water level and the right amount of sunlight, to take on its bright hues. During the wet season, the water of Caño Cristales flows too fast and deep, often creating small circular pits and thus, hiding the bottom of the river and denying sunlight to the Macarenia clavigera, which helps them to turn red. On the other hand, during the dry season, the water level of the river becomes shallow and insufficient for flourishing life in the river. But for a few weeks from September through November, the river becomes colourful under the right conditions and transforms into a rainbow river. The most important among the colours is numerous shades of red, which include pale pink to hot pink, blood red to maroon. However, red is not the only colour of the Rainbow River. The Macarenia Clavigera plant also turns bright green in shaded areas. In fact, the river during those weeks becomes ornamented with rich blotches of yellow, green, orange, blue and a thousand shades in between.

Caño Cristales is within the Serranía de la Macarena National Park park, which stretches over 100 km. The Park is a protected area covering 6,200 square kilometers. It is located at the point, where the Amazon rainforest, Andes mountain range and savannah plains of the East Llanos meet. It is a remote, isolated area, not easily accessible by road. It can be reached by airplane from Bogotá to La Macarena, or from Bogotá to Villavicencio and then La Macarena. La Macarena is a town located just outside of the National Park. Visitors can access the location only through the specialist tour companies.

The site was closed to tourists for about twenty years because of guerrilla activity in the region. It was reopened to visitors in 2009.