Fort Mountain State Park near Chatsworth is best known for a mysterious stone wall about 875 feet long that snakes across the mountaintop. Its origins are still debated, and legends about who built it add a sense of mystery to a visit. Trails lead to the wall, to a stone fire tower built by the Civilian Conservation Corps and to overlooks with sweeping Blue Ridge views. The park also has an 18-mile bike trail, a small lake for swimming and paddling, cabins and campsites for overnight stays. Parking is $5 per vehicle, and camping runs $20 to $42 per night. It is a good pick for hikers, mountain bikers and anyone who enjoys a good mystery.