Considering the vast amount of the Earth that is covered by water, it should be no surprise that there is a bevy of high strangeness connected to the high seas.
YouTube user Top5s has put together a collection of five fascinating mysteries which take place either on the water or, chillingly, beneath the surface.
Perhaps the most unnerving story on the list is that of Mexico's Sac Uayum sinkhole, an underwater cavern system that natives claimed was the domain of a horse-headed creature that feasted on humans.
Although one might ascribe such a belief to mere local legend, a scientific expedition into the sinkhole revealed that the story may be more than fiction as divers found the cavern littered with human bones!
Experts say the skulls were elongated and the bones did not appear to be from sacrificial rituals, suggesting that something very strange happened in that sinkhole which remains unexplained to this day.
Other captivating cases detailed in the collection include a man who disappeared while diving into a cave at a sight eerily called 'Vortex Spring' and the incredible Yonaguni Monument found beneath the ocean surface near Japan.
Dive in to the complete video to learn more about this bizarre oceanic events.