This Industrial Age architectural and engineering gem helps visitors and residents alike traverse Lisbon, “The City of Seven Hills.”

A king's pet, a pope's gift, an artist's inspiration, and a tragic shipwreck.

Before it was buried by volcanic ash, this fast-food restaurant fed the hungry hordes of ancient Rome.

This amazingly well-preserved villa just outside Pompeii boasts rare examples of ancient Roman paintings.

The walls and streets of the ancient city are peppered with penises.

Ancient snack bar of the Roman Empire re-opened.

Erotic art covers the walls of the largest ancient pleasure palace.

The last moments of the ill-fated Pompeiians, frozen forever in plaster.

The Cambridge pub where Francis Crick announced that he and James Watson had discovered the DNA double-helix.

Local legend says Isaac Newton built this footbridge without any screws, bolts, or nails.

A large replica of a monumental Roman inscription is located on the side of this museum.

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

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

This one-of-a-kind Roman arch is not actually dedicated to the god Janus.

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

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.

This large, circular tomb is the final resting place of the first emperor of Rome.

A huge enchanting public park just outside the ancient walls of Rome.

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

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

Jesus' footprints and the first catacombs in the world.