The Golly Hole, also called the December Giant is a very large sinkhole that appeared just south of the intersection of Shelby County Road 84 and Overhill Road in northern Calera in December 1972. It has been thought to be the largest sinkhole in the United States and one of the largest in the world.
The sinkhole appeared overnight when the roof of an underground aquifer collapsed. Nearby residents Herschel and Nora Byrd reported hearing the sound of trees crashing on the night of December 2. A group of neighbors located the hole while hunting a few days later. According to Mrs Byrd, they named the feature for the expression they used when they first came upon it.
The structure was part of the Knox group of Cambrian-era dolomitic limestone. The water table in the area was low due to industrial watering and drought conditions, allowing clays in the soil to shrink and crumble and accelerating the flow of groundwater through the soluble limestone.
Estimates of the size of the hole vary. The Alabama Geological Survey and other technical sources report that it is 325 feet long, 300 feet wide and 120 feet deep. Contemporary news accounts ranged to as much as 425 feet across and 200 feet deep.
The Golly Hole is currently on property owned by Vulcan Materials and is secured against trespassers.
- "Nation's largest sinkhole may be near Montevallo" (March 29, 1973) The Tuscaloosa News
- Sullivan, Walter (March 31, 1973) "Sinkhole drops alarm Alabama" The New York Times news service
- "The December Giant" (April 23, 1973) TIME magazine