It occurred to me that I can tell a ghost story that is not mine. Every Easter, a local church from Americus or Macon has a sunrise service out on the stockade site at Andersonville (I happened to be there for Easter one morning before the site was open to the public and could hear them singing through the fog).
One of the rangers needs to get there early to open the cemetery gate for them to pass through in order to get to the stockade. This particular ranger got there early, and, as it was both early and still dark, the ranger nodded off and fell asleep. Suddenly, a tapping on the car window woke them up, just as the first set of headlights came into view before turning into the cemetery entrance and stopping at the gate. The ranger muttered, "Thank you," and got out of the car to go enter the punch code to open the gate. Told me that they weren't scared at all and that it was definitely a tapping on the window that woke them up, and they had the sense that it was one of the prisoners who was still there, just being helpful.