Is There a UFO in Area 51?

One theory is that the UFOs are investigating this land and protecting it for some reason in particular. It's said that one of these tribes put a curse on this land, whether it was to deter the opposing tribe or because they lost the land. The only thing that kind of lends credence to this idea is people hearing large machinery underground. There might be some sort of radioactive mechanisms underground that is then poisoning anybody that gets close.