The largest waterfall on earth is under the ocean near Greenland.
The Denmark Cascade is an enormous downwelling of water near Greenland. It may be affected by global warming. (Photo : GettyImages)

The largest waterfall in the world, a cascade of cold, dense water, lies deep under the surface of the ocean. The water doesn’t fall over an escarpment or cliff, but it’s a waterfall just the same: As cold water hits warm water, it plunges in a cataclysm deep into the abyss. Instead of falling over rock, the water is falling over other water.

This underwater downward rush of water is the Denmark Cascade. Cold water coming south from Greenland hits warmer water coming north from Iceland. Where the two water masses meet, the cold mass falls 11,500 feet straight down in a massive downwelling that dwarfs any waterfall on land.

The cascade flows along the length of the boundary at an astonishing rate of 175 million cubic feet a second, almost 200 times greater than Inga…