Located in the little slice of ocean between Greenland and Iceland is the gigantic waterfall known as the Denmark Strait cataract. Its height is approximately 11,500 feet, while, in comparison, the largest waterfall on land is merely 3,212 feet tall. The Denmark Strait cataract is formed by the difference in temperature when the freezing Arctic waters meet the slightly warmer Irminger Sea. When that happens, the slides right down through it to the bottom of the ocean. This phenomenon is the key to the functioning of the deep-sea ecosystem in the area.