Originally built to protect the port of Philadelphia and Wilmington from invasion, then home to some 13,000 prisoners, Fort Delaware is a huge and imposing location. With so many different places over such a large area, the team has their work cut out, investigating the fort before sunrise.Originally built to protect the port of Philadelphia and Wilmington from invasion, then home to some 13,000 prisoners, Fort Delaware is a huge and imposing location. With so many different places over such a large area, the team has their work cut out, investigating the fort before sunrise.