When I was a student, the campus was located on what had only 20 years before been an old asylum for the insane. Like, batshit crazy people. They did lobotomies there and what not. Most of the buildings had been refurbished into "normal" school buildings with lecture halls, study group rooms et cetera. Seemed pretty normal, except the small study group rooms that only had one window, that was 1 square feet, 15 feet up on the wall, with bars in front of it. Yeah. Now, walking around the halls at night was creepy enough in it self, but one experience I will never forget.
I was the leader of a student/professor team that was in charge of evaluating lectures, professors, timetables et cetera, and we usually had our meetings after hours. This one time, we were sat in what used to be the old employee cafeteria (according to one of the old professors, who had been around for a long time). Now, I had seen the original blueprints from back when it was an asylum, so I knew what buildings had been the women's cell wing, the men's wing, administration (including morgue) et cetera. A little while into the meeting, suddenly all of us (8 people in total) turn at the same time, everybody hearing what seemed like a woman's scream coming from an open window towards the old women's wing. We all knew we were the only ones at the campus at the time (small part of a larger college), and we had all heard it – as evidenced by the fact that everyone turned their head.