This structure is Tennessee Valley Authority's largest rock-filled dam, measuring 230 feet high and 8,500 feet long. The 520-acre lake atop the mountain is a part of the TVA hydropower system. Take an amazing tour into the mountain, dam and powerhouse. After your tour, settle down to a picnic lunch at one of the many picnic areas or take in the view of the scenic Tennessee Valley where the mountaintop offers a breathtaking vantage point. Admission is free.