There is a river in Colombia that has been called the “liquid rainbow” and the “river of five colours” for good reason. The 62-mile-long Caño Cristales near the town of La Macarena contains brilliant reds, blues, yellows, and shades in between.
The effect is often thought to be the result of moss or algae but is actually caused by an aquatic plant called the macarenia clavigera. However, it only blooms red during certain times of the year; the peak season is, in fact, between September and November when the river has enough water to feed the plant but is also dry enough to allow sunlight to reach it. The other colors are provided by elements from the surrounding environment like water and sand.
While the river was previously closed to visitors because of guerilla fighting in the area, it is now accessible with help from Colombia’s military.