Sorry guys, no photo-ops on this one. Meet the Denmark Strait cataract, the largest waterfall in the world. The gigantic waterfall is located between Greenland and Iceland, stretching over 100 miles (160 kilometers) wide and plunging 11,500 feet (3,505 meters) down from the Greenland Sea into the Irminger Sea, as How Stuff Works details:
The most astonishing thing about the Denmark Strait cataract isn't, perhaps, how it got to be so tall and mighty, but that an undersea waterfall can exist at all. It's easy to picture an ocean as a giant bathtub that sloshes around with the tides, but seawater is actually very dynamic; waters of different temperatures and salinities — and, therefore, densities — are always interacting on large and small scales.
The Denmark Strait cataract is formed by the difference in temperature between the ultra-cold Arctic waters of the Greenland Sea meeting those of the slightly warmer Irminger Sea. Since the molecules in the cold water are less active and take up less space than in warm water, they are packed together more tightly, making colder water denser. That means that when water from the Greenland Sea meets the Irminger Sea water, it slides right down through it to the bottom of the ocean.
Image via How Stuff Works