Tell me a creepy story that made you believe ghost are real

My grandparents passed away a long time ago. They had a little house out in the country. One day I noticed that the front door was half open, and some animals were getting inside. Somebody must've been in there, so I bought a hasp and a lock for the front door. Just as I was putting the lock on the door, a bell that was hanging on the wall above the door started ringing. I had never heard that bell before, and it wasn't even windy out. I stopped what I was doing and I said "Ring the bell again if you don't want me to lock the house." Then the bell rang again. I took the lock off the door and I said "Fine, whatever" and then I left, lol.