The ocean is the single most massive entity encompassing the good majority of our planet. More people have stepped foot on the moon in the middle of space than have walked in the deepest portions of our oceans. That being said, humans have only explored about one percent of the seafloor. Mysteries abound in those hidden locales deep under the ocean blue. Here are 20 mysteries that science is having trouble explaining under the sea. These will make you wary of stepping foot in deep water the next time you’re on vacation