The term ?underwater? waterfall is not accurate, but merely an illusion when photographed from the air. From sea level, there is no ?waterfall? but rather nearly continuous shifting of the sand on the sea floor caused by two different tidal currents.

The "underwater waterfall" located off the coast of the Le Morne Peninsula in Mauritius is not a real waterfall, but rather a spectacular optical illusion. From a bird’s-eye view, it appears as though a massive torrent of water is plunging into the depths of the ocean. In reality, what you are seeing is the movement of sand and silt being pushed off a shallow coastal shelf into much deeper water by powerful oceanic currents. This "sandfall" creates a visual gradient of blues and greens that perfectly mimics the appearance of cascading water. The illusion is made possible by the island’s unique geological shelf, which drops from a depth of about 150 meters to over 4,000 meters into the abyss. While it isn't "falling water," it is a genuine natural phenomenon that is best viewed from a helicopter or seaplane, as the effect is nearly impossible to see from the shore or while swimming in the water.