The "Greatest Sewer" of ancient Rome is one of the oldest sewer systems in the world, and is still in use.

A fairy tale castle in modern Rome.

You've probably seen these distinctive orange-tiled columns on the big screen.

A monument to the three wars that led to German unification towers within a Berlin traffic circle.

Residents of Berlin take their coffee and cake in one of the city’s most restful spaces: a cemetery.

Thousands of coffin-like pillars make up this controversial Holocaust memorial.

A slice of central Asia in the middle of Berlin.

An interesting decoration on this historic site, this weathervane comes with as many legends as it does questions.

A former waterfront market is now in the center of town due to some interesting Boston engineering.

Mrs. Mallard and her brood are a beloved fixture in Boston Public Garden.

The American Revolution was galvanized into serious action due to the tragic clash with British soldiers that occurred at this location.

The oldest Italian café in Boston, this spot also serves as a veritable museum of vintage coffee ephemera.

Legend has it this fountain built to symbolize the Pope’s power hides a strange secret concerning Neptune's manliness.

This statue is the only female representation of Rome's "talking statues."

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

These hut foundations are believed to be the residence of Romulus, founder of Rome.

This curious, round temple is the oldest still-standing marble building in Rome.

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

Also known as the Square Colosseum, this building is a prime example of fascist-era rationalist architecture.

A detailed pachyderm supports Rome's smallest Egyptian obelisk.

Gods clash with machines in a power plant regenerated as a museum.

Inside this McDonald's you can dine on your Big Mac and fries next to a 2,500-year-old Roman wall.

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

The final resting place of the poets Shelley and Keats.