Tour the dark and beloved poet's former cobwebbed basement, which may have inspired "The Black Cat."

A swimming hole in the historic industrial quarry that supplied the marble for the Baltimore Washington Monument.

This suburban house is made of dirt, and almost sparked a revolution in home construction.

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

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

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

Dogs, cats, horses, monkeys, frogs, and fish are laid to rest at the second-oldest pet cemetery in the U.S.

The stone marker that Mason and Dixon placed at the eastern end of the famous north-south border they surveyed.

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

Historic home of America's sweetheart sharpshooter, Annie Oakley.

A star fort along the C&O Canal in western Maryland that protected America in three wars.

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

A haunting exhibit in a wildlife refuge center highlights threatened species and the conservation efforts needed to save them.

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

Built by the patriotic residents of Boonsboro in a single day.

This scenic Maryland park was the site of one of the worst prison camps of the Civil War.

Ship skeletons haunt Baltimore's waterways.

An eerie, decaying ghost town destined to fade into the forest.

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

This simple convenience store sits on the location where the Ouija board was named—and has a plaque to prove it.

Walk a trail through a historic Quaker town that outlawed slavery in 1777 and was a major waypoint on the Underground Railroad.

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

An FDR-era tuberculosis sanatorium has stood abandoned in the suburbs of the U.S. capital for over 30 years.

Fiji mermaids, mummified remains, and recreated cryptids are among the morbid oddities at this Maryland museum.