Built in the nineteenth century as one of three forts designed to protect the city of Philadelphia from attack, Fort Delaware served its purpose well and never had occasion to fire a shot in anger. Whether it was well-founded intimidation or simply a lack of opportunity that led to the fort’s nonviolent history, one thing remains clear: Fort Delaware offered a combination of strategy and firepower that would make any enemy think twice before breaching its territory.

Located on tiny Pea Patch Island in the Delaware River, the fort is a short, stout, pentagonal structure, exemplifying the prevailing architectural strategy of the United States military at the time: broad, flat walls that were easy to construct and even easier to defend.

Shirking the longstanding military tradition of European castles and forts that featured high, unscalable walls, 19th-century U.S. forts like Fort Delaware maintained the notion of having as many guns pointed in the same direction as possible (thus the broad walls), but with a vastly reduced vertical profile, making it much harder to hit with cannon and artillery fire.

And cannons were the primary concern of the fort, as it was explicitly a harbor defense structure charged with defending Philadelphia from seaward attacks that may have traveled up the river to outflank the city’s land-based defenses.

While its location was both deliberate and necessary, the fort never saw the sort of action it might be required to participate in – that of a powerful, invading foreign navy – instead spending most of its glory years as a support facility during the all-consuming Civil War.

Of course, Confederate forces did not venture within its range for the duration of the war. During the 1860s it became the base of a prisoner-of-war camp, housing captives from all over the South as well as many Northern dissenters. Again, its maritime location was the key to its utility, in this instance not for harbor defense but rather to use the surrounding waters as a means of preventing escape.

Today, like so many forts, it is both a park and a museum, serving as a beautiful and scenically located remnant of a more violent time, not unlike the tropical paradise of Fort Jefferson in the Caribbean or the Maunsell Forts in the United Kingdom.

Widely renowned to be haunted and a favorite site of many paranormal investigators, the fort is a popular destination for visitors who come to get a sense of local history and marvel at what it would have been like to prepare for the brutality of war in such a lovely place.