This small, ancient Roman temple was once a church dedicated to the patron saint of penitents.

A detailed pachyderm supports Rome's smallest Egyptian obelisk.

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

The only "Egyptian" pyramid in Europe and the legendary tomb of Remus.

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

Rome's semi-secret peephole vista is also a former Crusader stronghold.

A master of trompe-l'oeil creates a stunning, tourist-fooling dome out of a flat ceiling.

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

A French library that makes sure its love of books is writ large... giant in fact.

Balconies that have a most unusual accent.

One of Madrid's oldest trees, with a long and colorful history, resides in El Retiro Park.

An iconic and controversial ancient Iberian funerary urn with a hauntingly penetrating gaze.

Commonly acknowledged as the only public monument to the Devil himself.

A lush indoor jungle fills this bustling Madrid transportation hub.

This chimerical bridge/tunnel appears to dead end right into the sea.

Swedish skyscraper with a 90° twist.

This small museum nestled inside a souvenir shop is dedicated to Sweden's most well-known toy.

Stockholm's narrowest alley is barely over two feet wide.

The discovery of an old wall led to the creation of this fascinating museum about the city in the Middle Ages.

It is said that each of the white stones in the red facade of this medieval house represents the head of a murdered Swedish noble.

Sweden's "good old days" painstakingly re-created in a model village.

The library's graceful rotunda is like a bibliophile's temple.

It houses the remains of a 17th-century version of the Titanic.

Giant topiary dog once played a role in a terrorist bomb plot.