Archaeological zone 9UN367 at Track Rock Gap, near Georgia’s highest mountain, Brasstown Bald, is a half-mile (800 m) square and rises 700 feet (213 m) in elevation up a steep mountainside. Visible are at least 154 stone masonry walls for agricultural terraces, plus evidence of a sophisticated irrigation system and ruins of several other stone structures. Much more may be hidden underground. It is possibly the site of the fabled city of Yupaha, which Spanish explorer Hernando de Soto failed to find in 1540, and certainly one of the most important archaeological discoveries in recent times.