I can relate to ghosts being seen/felt near a Spanish mission, because we have one here in country Western Australia which was set up by Spanish Jesuits. Entities are stuck in that establishment due to their inability to let go of pain and suffering experienced within those walls.There was a Dr. Who episode along these lines. Of course the ghosts were bad aliens.
I do have a question along this line. What about very haunted places? Are the spirits still able to maintain their presence? I know there was period a few years ago when quite a few were able to find their way out of here.
I've been in a few places and had to leave because it was too much activity for me. One was the French compound in St. Augustine, Florida and another was a Spanish mission near Santa Barbara, California.