Now an entertainment complex, the Lingotto building was once an avant-garde auto factory with a test track on the roof.

Venice's island of the dead.

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

This demon atop the Notre-Dame de Paris looks utterly bored.

This saucy statue once caused outrage among locals.

Montmartre's sole surviving windmill became an iconic landmark for 19th-century painters, artists, and bohemians.

A memorial to the nearly 10,000 American soldiers laid to rest on the beaches of Normandy during WWII.

A massive, secret marina for the Nazis' most formidable weapon in the Atlantic.

The very center of Paris is surrounded by a bevy of strange good luck rituals.

This 1,300 year old monastery built atop a single rock was once only accessible depending on the whims of the tide.

An ancient knight and a symbol of the city's freedom.

A black cat protests the City Guild in Riga's Old Town.

The oldest housing complex in Riga is a mini timeline of architectural trends.

Have tea in a cemetery with a dazzling view of Istanbul.

Mediterranean castle on a tiny Turkish island.

This historic hotel preserves many treasures from its heyday hosting passengers on the Orient Express.

A section of the long chain that blocked enemy ships from entering Constantinople.

1513 Turkish world map, full of European state secrets and snarky commentary.

The deepest underground city in Turkey was designed to protect 20,000 people behind massive stone doors.

This remarkably well-preserved Egyptian plinth is pretty well traveled for a giant piece of stone.

A small etching on the white marble parapet was written in runic script by a Viking mercenary.

The ornate miniature mansions were built for Istanbul's feathered residents.

In this historic region, homes and churches are carved into ancient volcanic rock formations.

The giant statue and its model solar system honor the native Pole who declared that the Earth revolves around the Sun.