. "Civil War Defenses" . "Civil War-era fort used to defend the nation's capital" . . "defenses of Washington, DC" . . "Civil War Defenses of Washington" . "extensive fortifications" . . "American Civil War defenses" . "Fort Slocum Park" . . "Defense of Washington" . "Civil War Defenses of Washington, D.C." . "forts around Washington DC" . "Fort Chaplin" . "defenses of the Capital" . . "defenses of Washington" . . "Defenses of Washington" . . . . "Defenses of Washington D.C." . "Civil War Defenses of Washington, DC" . . "Civil War Defenses of Washington" . . "Fort Circle" . . "Defenses of Washington, D.C." . . . . . "Civil War defenses of Washington" . . "wartime defenses" . . "Fort Circle Park" . "defenses of Washington, D.C." . . . "Civil War Defenses of Washington \u2013 Fort Circle Parks" . "fortifications" . "artillery defenses of Washington, D.C." . . "74000274" . . "Fort Circle Parks" . . "defense of Washington" . . "artillery defenses of the Capital" . "fortifications built to defend the city" . . "defense of Washington, D.C., during the Civil War" . .