From a nearby Historic Marker:
...The onset of World War II caused a great expansion of the manufacturing and storage facility at Savanna, to include a one of a kind "Group 1" shell loading plant. It was this group 1 plant that was used to load the special light weight bombs used by General James Doolittle in his historical Tokyo Raid. The unique capabilities of Savanna ensured the depot played a central role in World War II and resulted in it being designated as an Enterprise "E" site with two Silver Stars....
The Savanna Army Depot closed down in 2000. Part of the land has been turned over as a natural prairie available to visitors. Some of the buildings have been leased to businesses. A large portion is restricted due to unexploded ordinance in testing grounds.
The main web site listed below has many photos of the area. Be aware that all comments are the views of the author. There is no documentation of proof cited by the author.