Caño Cristales, located in remote part of Colombia, is just your average river — most of the time. But a few times a year, the river turns into a literal rainbow of water. One picture is at the right, and Atlas Obscura has many, many more.
Caño Cristales is rich in many types of algae, and when the water level is just right, the algae feeds on the sunlight and glows. Reds, greens, yellows, oranges, etc. combine with the blue-appearing water. The river, also known as “The River of Five Colors,” is a sight to be seen — a flowing piece of natural artwork.
But for a long time, you couldn’t actually visit it. For three years ending late 2009, the Colombian government closed access to the river, citing security concerns, given the area’s paramilitary activity. The area is now open, but is still difficult to access. Tours of no more than 20 people depart a town two hours away, by foot (driving to Caño Cristales is not an option), and overnight stays in the area are forbidden in an attempt to preserve the environment. And one can only visit during the short periods each year when the river is in its abnormal, hyper-color state.
Bonus fact: There are few things as colorful as a box of crayons. Normally, a good person to attest to this fact would be Emerson Moser, who, in 1990, retired as Crayola’s senior crayon molder — with 1.4 billion crayons moulded over 37 years on the job. But Moser would be of no help: upon his retirement, he announced that he is colorblind.
Related: 120 Crayola crayons — for $7.