Now here me out, I understand that most people believe that mythological creatures such as sea serpents and unicorns are just fairytales. However, over the course of centuries and many excavations and iceberg readings, there have been a number of fossils possibly connected to such creatures we believe to be myths. As most people know (I presume), there was a fossil discovered in an archeological dig that claims they found a creature with a singular horn on its head like a unicorn though its body resembles that of a Rhinoceros in February 2016 and the fossils date back to 29,000 years ago! The Myth behind unicorns dates back to 400 BCE when a Historian named Ctesias first documented a unicorn-like creature in India and who knows how they were claimed to be frail like a horse compared to a Rhinoceros. If you search hard enough you can find plenty of details regarding this once mythological-now-historical creature. Unlike the sea serpents, who have never been archeologically discovered, I do believe they existed once long ago as well. I believe that the sea serpents were once guardians of the ocean and were hunted for sport and glory for warriors. You hear plenty of stories about sea serpents destroying ships and being hunted for such disasters. Fishermen dying at the hands of an unknown monster who lingered below the deep waters, it became so terrifying to the humans that we rewarded anyone who could bestow heads upon kings the riches their feats deserved. Even now in today's age, there are still some sea serpents I believe out there that hunt our submarines that cross their paths. These once hunted serpents do not come to the surface of the ocean anymore and lurk beneath the waters preserving the few numbers that are left. Since there is much of the ocean we have not discovered and probably will not in the near future, there is quite the possibility of there being skeletons of their fallen brethren on the ocean floor. I may not be one for the ocean myself but if there are such creatures lurking there, they most likely want to live their days without the unnecessary destruction of their kin.
If you would like to hear more about Mythological Creatures in History, I'd appreciate the feedback and any creature preferences you'd like to hear more about. I do most of my research freely on these topics anyway so please don't hesitate to ask.