Ft. Delaware, Delaware City. Used in the Civil War as a prisoner camp, Ft. Delaware housed 33,000 confederates. It was also used in the coastal defense networks of WWI and WWII. Since it’s opening to the public in 1951, visitors and employees have reported the sounds of moaning and chains rattling in the dungeons of the fort. The apparitions of confederate soldiers have been seen under the ramparts and in the parade grounds.