Fort Fisher was the largest and strongest seacoast fortification in the Confederacy, and the main guardian of Wilmington, North Carolina. Located near New Inlet, the northern-most entranceway into the Cape Fear River, Fort Fisher's earthen batteries stretched for about one mile and mounted forty-seven heavy seacoast cannon that protected blockade-running ships smuggling vital supplies into the Confederacy by way of Wilmington. From 1863-1865, Wilmington was the South's principal seaport and considered the lifeline of the Confederacy. Fort Fisher withstood the most intense U.S. naval bombardment of the Civil War at Christmas 1864, before falling to the largest Union combined operation up to that time in mid-January 1865. Federal authorities were so impressed with the size and strength of Fort Fisher that they determined to make a photographic record of the imposing stronghold for posterity. Alexander Gardner, who did considerable photographic work for the U.S. Army, dispatched one of his best employees, T.H. O'Sullivan, to photograph Fort Fisher. In early February 1865, O'Sullivan made a series of about forty views of Fort Fisher, making it one of the most photographed Confederate fortifications