Fort Delaware's moat, at least at the time the fort was being used for its intended purpose, was gross. Fort Delaware was reportedly the very first such structure in the US to enjoy indoor plumbing, at the cost of everything being drained into the moat, which became predictably aromatic, particularly in the summer. Efforts were made to connect the moat to the Delaware River in a fashion that would circulate the moat's water, but this never really did the job. Fortunately for me during my visit, it has been a great many years since poop has floated in the moat.