This city and the county are named for a subterranean rock formation that has been the subject of study for years. Although there has been speculation the wall was built by prehistoric man, geologists think the phenomenon is a finger of the Balcones Fault in which the "wall" was formed by geologic stress splitting the formation. Rockwall has scenic, rolling hills and sits on the shores of Lake Ray Hubbard. A golf course is near the lake.