Fort Pulaski, located on Cockspur Island at the mouth of the Savannah River, was built between 1829-1847 to help defend the city of Savannah. During the Civil War, Union forces used new rifled artillery to breach the fort's thick masonry walls in less than 30 hours, the first case where coastal fortifications were defeated primarily by artillery fire. Fort Pulaski is now a national monument preserving the fort and commemorating its role in improved coastal defense technologies during the Civil War.

1. http://www.georgiaencyclopedia.org/articles/history-archaeology/fort-pulaski
http://en.wikipedia.org/wiki/Battle_of_Fort_Pulaski
http://en.wikipedia.org/wiki/Fort_Pulaski_National_Monument
http://www.ri.net/RIEMA/bibliog.html