Not all monsters live in haunted houses! Some swim just under the waves. August 7th — National Sea Serpent Day — is for the beasts we rarely see but never stop imagining. In coves, creeks, lakes, and oceans across North America, long-bodied creatures have stirred panic, awe, and centuries of speculation. Legends aren’t born from nothing — especially not the kind told by sober sailors, stunned sheriffs, and terrified tourists. These are the top 10 North American sea serpent encounters that refused to sink quietly into myth.

Lakes are beautiful on the surface—but beneath their still waters often lie chilling secrets. For centuries, these seemingly peaceful places have been the setting for ghostly apparitions, phantom hitchhikers, and monstrous creatures that defy explanation. From women in white wandering the shorelines to serpent-like beasts slipping through the depths, haunted lakes across the world are steeped in legend, mystery, and fear. Here are five ghost-ridden lakes and five legendary lake monsters that continue to captivate—and terrify—those who dare to look beneath the surface.