Connor Cornelius | Travel on Instagram: "This “underwater waterfall” in Mauritius is one of the most fascinating natural illusions you’ll ever see. From the air, it looks like the ocean is dropping into a massive void, but it’s actually sand and silt being pulled over the edge of an underwater shelf by strong currents. The effect is so striking it feels impossible, even when you know what’s happening. Helicopter tours give the best perspective, but the thought of diving near it and watching the