There are number of strange, forgotten sights in Philadelphia that in any other city would be a major, if not the major tourist attraction. Fort Mifflin may be the best of these sights in Southwest Philadelphia. The fort is enormous and nearly always empty. Within its walls, spread out on a huge lawn, are cannons and carriages, officers' quarters, soldiers' barracks, an artillery shed, a blacksmith shop, a bomb shelter, and a museum. The exhibits are dated, but the stories are fascinating, from the 40-day battle in 1777 to hold off British ships coming up the Delaware to the use of the site as a prison during the Civil War. The fort was almost totally destroyed during the Revolution, but was rebuilt in 1798 from plans by French architect Pierre L'Enfant, who also designed Washington, D.C. If you wander off beyond the fort and into the other parts of the 49-acre National Historic Landmark, you will find a long embankment of overgrown and unexcavated battlements from the 1800s. From Penn's Landing it's an easy jaunt on I–95.
Island and Hog Island Rds., on Delaware River near Philadelphia Int'l Airport, Philadelphia, Pennsylvania, 19153, United States