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

The tallest The Church of Jesus Christ of Latter-day Saints temple in the world soars above the Beltway.

An isolated island home to one of the oldest English-speaking communities in the region and Maryland's state dessert.

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

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

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.

Rediscovered after a century, the father of the American Navy was reinterred in something dredged up from Davy Jones' Locker.

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.

A faded sign from the 1920s remembers Baltimore's resistance toward banning alcohol.

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

An eerie, abandoned military base engulfed by nature and graffiti is now home to a local park.

Captain John Smith thought these cliffs were amazing in 1608 but sharks thought so 20 million years before him.

This abandoned sea fort has become an accidental bird sanctuary.

After hundreds of years of settlement, this once-bustling fishing village sunk into the Chesapeake Bay.

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

This dig site outside D.C. is known for its exceptionally high density of baby dinosaur fossils and dinosaur eggs.

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

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

The ruins of this long-abandoned unsuccessful gold mine can still be found.

Despite violent work crews and massive delays this abandoned canal tunnel was built to last into the modern day.