Fort Pulaski
After the war of 1812, President James Madison planned a system of coastal forts to protect the country from foreign invasion. As result of the order, construction of Fort Pulaski began on Cockspur Island in 1829. Its location on the Savannah River was chosen as a means to protect the city of Savannah and it's critical trading port. After 18 years, a million dollars and 25 million bricks, Fort Pulaski was finally complete.
Fort Pulaski was given its name in honor of a Polish commander, Casimir Pulaski, that fought under George Washington in the American Revolution. Pulaski, often considered "The Father of the American Cavalry," is most renowned for his contributions in the training of revolutionary militiamen and his participation in the defense Savannah and Charleston from the British. Pulaski was fatally wounded during the 1779 siege of Savannah.
In a strange turn of events, the United States had to conquer Fort Pulaski before they could use it. At this point, Fort Pulaski's history hits center stage. Following the succession of South Carolina from the Union in 1861 the fort was sized and inhabited by Georgia's militia. Later the same Georgia militia transformed itself into Confederate soldiers.
Even though the fort was considered unbreachable from the distance a typical cannon or mortar could be fired from, the Union army's experimental rifled cannon guns were able to penetrate Fort Pulaski's thick walls from nearly a mile away on Tybee Island. These rifled guns were able to cause overwhelming damage to the fort's structure. In fact, when a Union Army projectile impacted the wall of the northwest powder magazine, the Confederates were forced to surrender. Had the projectile penetrated the powder storage, it would have been catastrophic for the forts occupants. The use of the rifled cannon against Fort Pulaski marked a change in the direction of fort construction. Masonry fortifications would no longer be considered state of the art.
For more information please see http://www.nps.gov/fopu/