Fort Sumter is a sea fort located in Charleston Harbor, South Carolina, and notable for two historic battles of the American Civil War. It was one of a number of special forts planned after the war of 1812, combining high walls and heavy masonry, and classified as Third System, as a grade of structural integrity. Work started in 1829, but was incomplete by 1860, when South Carolina seceded from the Union. It is open for public tours as part of the Fort Sumter National Monument operated by the National Park Service. The First Battle of Fort Sumter opened on 12 April 1861, when Confederate artillery fired on the Union garrison. These were the first shots of the war, and continued all day, watched by many civilians in a celebratory spirit. The fort had been cut off from its supply line, and surrendered next day. The Second Battle of Fort Sumter (8 September 1863) was a failed attempt by the Union to re-take the fort, dogged by rivalry between army and navy commanders. Although the fort was reduced to rubble, it remained in Confederate hands until it was evacuated as Sherman marched through South Carolina in February 1865.Fort Sumter is now a National Monument with a Visitor Education Center.