**NO SPOILERS (yay)**
I have never been scared by horror movies. At least that was true about an hour and a half ago. This was the most terrifying thing I've seen. I know most won't agree with me but the documentary style of film and the lack of creepy music (for the most part) really adds a sense of realism. There were also a lot of very real situation that would arise from going into catacombs, i.e. small spaces, steep drops, no light, etc. The supernatural just amplifies the terror. If you're looking for jump scares or gore, this is not the movie for you. That being said I still highly recommend this movie.