The ocean as we know it is a very big and mysterious place. Many have rightfully dubbed it a "second world" and that is accurate because it is a place that is very different from the world above. And not unlike the land we live in, the waters of the world have deep places and secrets. For the longest time, the biggest secret was that of the Mariana Trench, which was so deep that none could reach it. Now, five have, and while it's still very much mysterious, we can at least say we know some of what's down there. Allow us to show you 20 Mysterious Things Found In The Mariana Trench!