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

The whole world in one water tank.

Two dozen pinball games hidden away inside a most unlikely location.

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

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

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

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

Remains of a historic fountain that was mysteriously lost in the demolition of a D.C. traffic circle.

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

The design of this historic domed church was influenced by Thomas Jefferson and intended as a statement of religious freedom.

Live data is transmitted from the Atlantic coast to instantly recreate the ocean waves in this fountain at the NOAA headquarters.

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

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

Bizarre Cavern.

The site where Poe "in great distress, and ... in need of immediate assistance" likely died.

Crammed into a Baltimore row house is an oddities shop that sells everything from skulls to dead insects.

It's not hard to see why the historic Peabody Conservatory of Music's library has been described as a "cathedral of books."

The trials and tribulations of marking Poe's grave.

The haunting "Hell House Altar" is one of the few remnants of an abandoned college that has been a magnet for local legends.

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

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

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

This bug-eyed water wheel uses the power of the Sun to clean up Baltimore Harbor.

This abandoned sea fort has become an accidental bird sanctuary.