Military in Maryland

This grove was planted more than a century ago by the War Mothers of World War I.

This four-story steel sphere in Maryland was used to test biological weapons.

A remote horde of architectural treasures fit for Indiana Jones.

Three abandoned missile silos are hiding in plain sight behind a suburban development in Maryland.

The Forest Service's surprisingly sophisticated collection of wildfire prevention art features America's most beloved bear.

Proto-CIA agents trained with grenades in the sand traps and fired machine guns from the fairways.

A mammoth pair of Civil War artillery guns abandoned out in the forest.

This massive swimming pool is the high tech home to the human-powered submarine races.

This beautiful stone arch bridge wasn't even expected to stand for one day, but people have been crossing it for centuries.

This one-room cabin where the young colonel slept during the French and Indian War.

This 16-foot, intricately detailed model of the Gearing-class destroyer has been called the most detailed model ship ever built.

The 320-year-old tree that greeted General Lafayette and rerouted an interstate highway.

This fort down the Potomac from Washington, D.C. was once the only defensive fort protecting the capital.

Once America's tallest structure, now a Baltimore landmark.

One of the only memorials dedicated to journalists who died in combat.

A cave on the Maryland border where civilians took refuge during the bloodiest battle of the Civil War.