These incredible pictures by Russian photographer Anatoly Beloshchin show what appears to be an underwater river.
The eerie phenomenon, deep inside a cave system in Mexico’s Yucatan Peninsula, is a three-foot layer of hydrogen sulphide separating freshwater from the denser salt water below.
The result is two distinct layers that give the impression of a river observed by divers who appear to float above it.
Added to the effect are the branches strewn where the two layers meet.
It is found in a cave called the Cenote Angelita (Little Angel Sinkhole), 29 metres below the surface.
Beloshchin has a website dedicated to his stunning underwater photography so be sure to check it out.