In the mid-1920s, before the Great Smoky Mountains National Park was established, North Carolina and Tennessee agreed to build a road through the center of the proposed park. The previous road topped the ridge through Indian Gap, but the new paved road was planned a few miles to the east, through Newfound Gap. The park employed engineer and “master road builder,” John L. Humbard (1892-1955) to oversee the project. Two tight switchbacks were replaced by a wide 360-degree curve, giving the road its distinguishing feature: a road looping over itself. At 5,048 feet, Newfound Gap is located near the geographic center of the park, becoming highway 441 passes through the gap. President Franklin D. Roosevelt dedicated the park at this site in 1940....