Secrets of Desolate Evil

Evidence of an unspeakable evil in a set of Parisian buildings and an alien Stonehenge with a sinister purpose are now abandoned ruins; experts investigate the secrets of these dark structures to uncover how they were built and why they were abandoned. This episode is a mashup of S06E10 "House of Horror," S02E08 "Sea Fortress of Doom," and S03E10 "Secrets of Alien Stonehenge."