The largest waterfall on Earth is hidden beneath the ocean. And you could sail above it without ever knowing it exists. 🌊 Between Greenland and Iceland lies the Denmark Strait Cataract, an underwater waterfall that plunges roughly 3.5 kilometres (2.2 miles) along the seafloor. But how can a waterfall exist underwater? ❄️ Cold, dense water from the Nordic Seas flows beneath warmer water and spills over an underwater ridge into the deeper North Atlantic. 🌊 Its estimated flow exceeds 3 million cubic metres of water per second - an astonishing volume that no river on land can match. 🌍 This hidden cascade helps drive the ocean's deep circulation, which transports water, heat and nutrients around the planet. Unlike a waterfall on land, it produces no towering splash or thunderous roar above the surface. Its immense movement unfolds in the darkness of the deep ocean. The ocean hides wonders that make the surface world seem small. If the world's largest waterfall is invisible from above, what other enormous natural phenomena are we still missing beneath the waves?