Watch FMovies. A cave named 'Gruta de las Pesadillas' was known to be a place whereby entering the cave with a torch or lamp, you would see your darkest nightmares reflected onto the shiny minerals from the inside. I was given access to a written document describing the experience of a man at the cave in 1914. He writes about leaving his house, going to the cave, and his experience there—This film is a visual and sonic recreation of the described event.