For most of the year, Caño Cristales in Serrania de La Macarena, Colombia is a normal river. But for a brief period between the wet and dry seasons, Caño Cristales explodes with kaleidoscopic algae straight out of another dimension.
From Atlas Obscura:
Caño Cristales is a succession of rapids, waterfalls, and manholes with a water of such purity that allows see the bottom easily. The Macarena Reserve which is about 130 kilometers long by 30 kilometers wide is also home of a rich and large variety of flora and fauna and a scientist at the Smithsonian Institute in the U.S., argues that the Serrania de la Macarena is one of the richest place in the world in forms of animal and plant life.
Kind of reminds you of the sewer scene from Ghostbusters 2, no?
[Spotted on Environmental Graffiti]