The ruins of the largest gladiatorial school in Rome are largely hidden under modern streets.

This ancient Roman prison is decorated with an upside-down cross not as blasphemy but as saintly tribute.

An ancient Roman temple first dedicated to an emperor's wife is now a church.

The only remaining arch of the oldest stone bridge in Rome stands in the middle of the Tiber.

This is the oldest Roman-made bridge in the city still existing in its original state.

The remains of this 2nd-century Roman temple are incorporated into a modern building.

This ritzy Italian market is built around a statue of an unforgiven heretic who was burned for his belief in an endless universe.

Look closely and you’ll notice that the color changes a third of the way up the tower.

Austin’s nonprofit-run graffiti park where street art is meant to be painted over.

Well-dressed pickle turned patriotic joint statue in old town Tomball.

The only airport with a people mover system designed by Walt Disney Imagineering.

A venerable restaurant chain's one-off attempt to blur the line between themed eatery and amusement park

This free sculpture garden is home to over 90 artworks and installations from artists around the world.

A small park on Bourbon Street features life-size bronze statues of New Orleans musicians.

The 5.5-mile ring of steel posts around the Capitol Building is one of the largest (and most uniform) of its kind in the world.

Decades before the scandal, this staircase on the river was a literal "water gate."

Those with a sharp eye can find the hidden image of a German Shepherd on the memorial's Mural Wall.

A gift from Japan, 17th-century lantern stands among the cherry trees at D.C.'s Tidal Basin.

An overlooked memorial honoring the local Washington residents who died in World War I.

The final resting place of an unidentified revolutionary soldier sits behind a Virginia church.

This historic lighthouse was well known for the large number of women who served as its keeper.

The childhood home of the Sultan of Swat is just a line drive away from Oriole Park at Camden Yards.

A 200-year-old bar with a cheeky name claims to have served Edgar Allan Poe his final drink.

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