From: Haunted Gettysburg by Jack Bochar & Bob Wasel
A couple of uniformed Civil War reenactors were taking in the sights on the battlefield when they decided to visit Bip Roundtop. They were driving at a low speed, with the windows rolled down to allow the best view of the area, making an occasional stop. They crossed Emmitsburg Road and went on at the low speed still taking in the sights, when they heard soft voices in conversation. At first they thought it was the radio but soon discovered it was off. They had a strange desire to find out where the voices were coming from and, consequently, believing the voices to be from a near by picnic area, drove into it.
Once in the picnic area they found nothing - not a soul to be found. The two men, confused and questioning their own minds, continued their journey to Big Roundtop. Reports of people hearing voices, cannon shots, muskets, and noises of all description, only to find there is no source for the unexplained sounds, are a common occurance on the battlefield.