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

Brass cobblestones mark the places where individual Holocaust victims were taken from their homes.

A mysterious chasm in the heart of the ancient Roman Forum, the Lacus Curtius was once believed to be a gateway to hell.

This ancient market is often referred to as the oldest shopping mall in the world.

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

A forgotten "city of water" underneath the famous Trevi district.

In Rome’s Jewish ghetto, a 200-year-old bakery still makes the neighborhood’s historic sweets.

The engineering wonder and pleasure dome of a much-maligned emperor still holds undiscovered secrets.

2300-year-old Roman road connecting the empire.

The skull of the patron saint of lovers lies in the Basilica di Santa Maria in Cosmedin—maybe.

The yawning maw of this pagan visage is said to bite off the hands of liars.

Rome’s legendary peephole vista is also a former Crusader stronghold.

Hundreds of lucky felines haunt the ruins where Caesar was murdered.

This was once the largest four-sided clock in the world (yes, even bigger than Big Ben).

This rooftop sign has been confusing Milwaukee-bound airline passengers for decades.

A trailblazing sovereign nation tucked in the American state of Wisconsin.

This abstract sculpture is rumored to cast a hammer-and-sickle shadow once a year.

A 400-foot-tall tall map of Chicago makes this once-ignored building stand out.

The twin towers in this Chicago fountain use 50 foot tall video screens to spit on people.

An outdoor urban gallery of large-scale artworks by the world's most influential street artists.

A century-old hotspot for jazz, frequented by everyone from Charlie Chaplin to Al Capone.

A once-booming Mississippi River town with a history of racial violence is now eerie and mostly abandoned.

Instead of becoming a power plant, this abandoned complex became a massive letdown.

This two-room shotgun shack in Tupelo is the birthplace of a King.