An undersea river in the Black Sea
Crazy as it sounds, scientists discovered a hidden river that follows along the bottom of the Black Sea in 2016. The river’s layers of dense water were formed when sinkholes became filled with saltwater.
The water moves at the ocean floor at a rate of a half-mile per day. Nobody would ever think it could be possible to find a whole new world under the Ocean. If on land, this river would be the sixth-largest river on the planet.