I know this is going to sound crazy coming from me, but does anyone here know anything about the supernatural?

Yesterday for four hours at my school, there was this really eerie bell tolling sound resonating throughout my entire school's south campus, going on even after school, for over four hours. It was far too periodic. I swear, it sounded exactly like the Slenderman soundtrack, except creepier, more echoed, and more church-bell like—a low resonating tone that, if I tried to walk towards its source, it'd appear to shift. At one point it got *very loud* behind a brick wall that I could'nt see behind, so I quickly went to the door leading outside. The bells abruptly stopped. I went outside and looked around, and nothing was there. Nothing that could have made the noise. I don't think it was Universal Studios (my school is right across the street) as it sounded very close, and Universal would never need to make such a noise. All the construction guys at my school left hours before. What made the noise >.>