Fort Monroe

Fort Monroe (also known as the Fort Monroe National Monument) was a military installation in Hampton, Virginia—at Old Point Comfort, the southern tip of the Virginia Peninsula. Along with Fort Wool, Fort Monroe guarded the navigational channel between the Chesapeake Bay and Hampton Roads—the natural roadstead at the confluence of the Elizabeth, the Nansemond and the James rivers. Surrounded by a moat, the seven-sided stone fort is the largest stone fort ever built in the United States.

• http://en.wikipedia.org/wiki/Fort Monroe