Dennis Martin was on an annual camping trip to the Great Smoky Mountains National Park when he disappeared on June 14, 1969. Martin, 6, from Knoxville, Tenn., had joined his father, grandfather, and older brother for their yearly Father’s Day excursion when he went to hide in a bush with some other children near the family campsite. Martin’s father saw him go behind the bush at 4:30 p.m. The plan had been for the children to jump out and surprise some other adults who were supposed to arrive at the campsite. When Martin did not come out for five minutes, his father began searching for him. But the boy was gone.
Park rangers were notified and a massive search effort was undertaken. The rescue effort involved 1,400 people and spanned a 56-square mile area, making it the largest search effort ever in the history of the Great Smoky Mountains National Park. Footprints, a shoe, and a sock were eventually found but not the boy. The search was called off Sept. 14. Martin remains missing.