Caño Cristales

Is it the River of Seven Colors? Or a more prosaic five? Guides toe the party line du jour of five: black, green, white, yellow, and bold ruby red. The plants (yes, plants, not algae) supply the red or green depending on the time of year, and the rocks and sand fill the whole spectrum. More investigative/imaginative/trifling travelers will find six or seven, though. The walk along/through the river is simply spectacular. With all the interesting rock formations, natural pools, rapids, and waterfalls, it would be a truly beautiful river even without the crazy red plants.

• outdoors