With no shortage of terrifying animals concealed by the oceans' unfathomable depths, it is not surprising that mariners of old imagined that they may contain even more secrets. What mythical sea creatures might still possibly swim among us?

Mermaids: Half-fish, half-woman, and all woman. Most historians now agree that mermaids were actually just manatees with whom sailors fell in love from afar, although this argument is quickly dispelled by knowing what a manatee looks like.

Lake Monsters: From Nessie to Chessie, most lakes are said to contain at least one serpent or plesiosaur, typically thought to have been long preserved in the glacial ice that eventually thawed to make the lake itself. In reality, these aquatic apparitions are just the silhouettes of logs, but that doesn’t mean there isn’t a real-world wonder there for you to marvel at—it’s the human imagination!

Krakens: These massive, huge, massive sea monsters were or are carnivorous fish or giant squids, or possibly octopuses (octopi?) whose massive size was (is?) concealed by the even more massive ocean. While we may never know for sure whether or not these creatures are real reptiles (or cephalopods? Wait, what are eels? Amphibians?) there is one thing that we know for sure: very little.