Where is Earth’s Largest Waterfall?

Rivers plunging through Earth’s deep gorges can produce spectacular waterfalls, natural wonders that attract millions of people with their dramatic beauty, immense scale, and tremendous force. Yet even the greatest waterfalls visible on land are dwarfed by enormous cascades hidden deep beneath the ocean.

The largest waterfall on Earth is located beneath the Denmark Strait, the stretch of water separating Iceland from Greenland. Deep below the surface, a series of underwater cataracts begins roughly 2,000 feet beneath the strait and descends to around 10,000 feet near southern Greenland. This creates an extraordinary vertical drop of almost two miles.

How Can a Waterfall Exist Beneath the Ocean?

Underwater waterfalls are possible because cold seawater is denser than warm seawater. In the Denmark Strait, extremely cold water moving south from the Nordic Seas encounters the warmer waters of the Irminger Sea. Because of its greater density, the frigid water sinks beneath the warmer layer and then spills downward across the enormous step in the seafloor.

This powerful underwater current is estimated to carry more than 123 million cubic feet of water every second. Despite its enormous scale and energy, the waterfall cannot be seen from the ocean surface. Since the turbulent flow takes place far below the waves, its immense movement remains hidden unless scientists use specialized instruments to detect and study it.