For a few extraordinary months each year, a remote river in central Colombia appears to transform into a flowing rainbow.
Brilliant shades of crimson, pink, yellow, green, blue and black ripple across the riverbed, creating one of the world's most remarkable natural spectacles.
Known as Caño Cristales, this breathtaking waterway is often called the "River of Five Colours" or the "Liquid Rainbow".
Yet its vivid appearance has nothing to do with minerals, pollution or optical illusions.
Instead, it is the result of an exceptionally delicate ecological balance involving sunlight, crystal-clear water and a rare aquatic plant found almost nowhere else on Earth.
