Anatoly Beloshchin is a professional photographer and diver. Recently he travelled to Mexico, and dove in the Cenote Angelita. Another name for cenote is sinkhole, and it's formed by the collapse of cave walls. The floor of these natural wells is covered with water. An exciting fact is that cenotes are mostly found in Mexico. Anatoly managed to take photos of a truly unique natural phenomenon when diving: an underwater river.
The deep sinkholes of the cenotes have filled with fresh rain water. Sea water rich in hydrogen sulfide is much heavier than ordinary water. Because of this, it sinks down and forms a stream, looking exactly like a real river on the surface. The underwater river is formed when the fresh top water meets the exposed salty groundwater. The different density level in the two waters causes them to layer.
To take photos, the diver had to dive down to a depth of 60 meters underwater. If you take a closer look, you can see sand banks, snags, and fallen leaves. All in all, it looks just like an ordinary river.