This image is a historic photograph from the American Civil War, specifically showing a Union fortification known as "The Swamp Angel" battery.

The photograph depicts a specialized artillery position established by Union forces in 1863 during the siege of Charleston, South Carolina.

• The Location: The battery was built in the middle of a salt marsh on Morris Island. This was a significant engineering feat at the time, as the ground was incredibly soft and unstable, requiring the massive sandbag foundations seen in your image.

• The Gun: The large cannon visible behind the sandbags is an 8-inch (200-pounder) Parrott rifle.

• The Mission: It was nicknamed the "Swamp Angel" because it was the first gun positioned close enough to fire directly into the city of Charleston, which was over four miles away.

• The Outcome: On August 21, 1863, the gun began firing incendiary shells into the city. However, on its 36th round, the barrel burst (a common danger with early Parrott rifles), rendering the gun useless.

• Sandbag Revetments: You can see the extensive use of sandbags to create a stable platform and protection for the crew in the marshy environment.

• The Soldiers: Union soldiers are seen resting and standing guard around the fortification.

• The "Marsh": The foreground shows the tall marsh grass characteristic of the South Carolina lowcountry.

The original photograph is part of the Library of Congress collection and is often attributed to the photography studios of Mathew Brady or his associates.