Heralded as the world's first theater, these ruins are often overlooked as they reside in the shadows of the Acropolis.

The oldest cemetery of modern-day Athens blends the modern and ancient worlds.

An unusual sculpture, an interesting history, in a strange place, for a good cause.

A historic cemetery with unique artwork, a Civil War fort, and also happens to be the site of the Battle of Bladensburg.

An enormous overgrown greenhouse teeming with graffiti and wildlife.

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

This ruined quarry once produced the distinctive red sandstone used for construction projects in Washington, D.C.

This advertisement for talcum powder was painted on the rock face and has since defied removal.

Series of storm drains connected to a dark urban legend.

This tiny New Jersey village has lived many lives but seems determined to remain a ghost town.

This semi-hidden Manhattan restaurant is based out of a loading dock.

Cheap pizza and all of your naughty bedroom needs housed in a stunning example of Art Nouveau architecture.

This giant satellite antenna services the transmission needs of government agencies and cable programmers.

This 1830s store is believed to be the site of Harriet Tubman's first stand.

One of the oldest surviving Swedish-American homes in the United States.

Museum houses an impressive display of the origin and artistry from the now-quaint invention's history.

A scenic fort on the harbor protected Philadelphia from an attack that never came.

This collection of odd proofs of concept is like taking a walk through the imagination of a Victorian engineer.

A secretive collection featuring objects that were designed specifically for U.S. intelligence operations.

A gorgeous mural outside a beloved D.C. restaurant pays homage to famous Black Americans.

Was there a small "backpack nuke" hidden in the attic? JFK apparently thought so.

A replica of the famous memorial statue at the Normandy American Cemetery hides in an office building in downtown D.C.

Four bald cypress trees in Lafayette Square, across from the White House, mark the southern edge of a 100,000 year old cypress swamp.

The winding route passes through an enclosed alleyway, two tunnels, and leads to the White House basement.