Federal forces continued to lay siege to Confederate forces holding defensive positions in South Carolina's Charleston harbor area. From late July of 1863 until early September of that year, Union forces were intent on reducing Confederate fighters defending Charleston — where the Civil War broke out at federally-held Fort Sumter in 1861. The prolonged federal siege began after a failed assault July 18, 1863, on Confederate defenses at Fort Wagner — led by a courageous black regiment which suffered heavy loss of life. It would not be until Sept. 7, 1863, that Confederate foes would abandon Fort Wagner when their position there became untenable. This week 150 years ago in the Civil War, the Confederate submarine H.L. Hunley arrived by train at Charleston after its construction in Mobile, Ala. It was billed as the world's first successful submarine and seen as a secret weapon for the South in fighting Abraham Lincoln's wartime blockade of Southern seaports.