Rome's ancient Etruscan rival, now a park full of ruins.

This abandoned island off the Venetian coast has been a radical monastery, a political prison, and a secret Nazi base.

This winding road through an Italian canyon may be the most scenic drive in the world.

Over 50 exquisite hand-painted Renaissance maps decorate a Medici storage room.

This zoological museum began as the first great curiosity cabinet.

Oldest Museum of the Netherlands is a true cabinet of curiosities.

This impressive collection of rare books on ancient mysticism inspired author Dan Brown.

An Amsterdam street lined with antique shops each one dedicated to a different obscure collection.

Peek through a transparent pyramid and drink in the mountain made of books.

The design of this beautifully crafted building was inspired by Norwegian glaciers.

Deep in a Polish forest, this collection of Iron Age megaliths still holds onto many of its ancient secrets.

Boats must transform into railroad cars to navigate this Polish canal.

Men in rubber-soled boots serve as your "brakes" on this toboggan ride Hemingway described as "exhilarating."

A neolithic tomb converted into a tiny chapel.

"Portugal's Stonehenge" is made up of nut-like stones aligned with the heavens.

An ancient and majestic fortress that played an integral role in Portugal's road to independence.

Houses are tucked between, on, and underneath giant boulders.

One of the most beautiful bookstores in the world hides a neo-Gothic interior behind an art nouveau facade.

Once an opulent Art Nouveau hotspot, the Constanța Casino is one of Romania's most beautiful abandoned buildings.

Imperial palace of Emperor Galerius, the Emperor behind the worst Christian persecutions during the Roman Empire.

Stone age urban planning.

This massive subterranean fissure is known as the "underground Grand Canyon."

A 12th century church completely covered in shells.

Whether they are bulls or pigs, these ancient animal sculptures are fascinating relics.