Two stunning 17th-century libraries and a cabinet of curiosities.

Kings Cross Station pays tribute to its role in Britain's best-selling book series.

A small island less than half a mile from Venice is a forbidden island with a dark and twisted past.

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

Famously misunderstood wonder of the ancient world

The former Nazi concentration camp stands as a museum to remember this dark chapter in European history.

A museum dedicated to a secret military hospital hidden beneath a castle in Budapest.

Barcelona's historic 19th-century sewers, whose foundations were laid in medieval times, are open to the public for exploring.

A vista of the city and sea from atop the little-known viewing deck on an unassuming Columbus statue.

Take a giant yellow bird cage to the top of Elba's highest mountain.

A marvel of technology a century ago, this disused power station now offers a lovely glimpse into the industrial design of the past.

This former Cyprus flight hub is now a crumbling, abandoned ghost complex.

This massive underground salt mine now holds a sci-fi theme park in its depths.

Check out engineering marvels of the past at this unintentionally retrofuturist museum.

A wonderfully strange collection of 500+ stuffed frogs doing people things.

Yugoslavia's biggest underground airport lies in ruins.

Enter the cabin of a life-sized Hindenburg replica.

The world's greatest slide descends 18 stories from this looping mountaintop viewing platform.

Ruins of a German Castle on top of a towering stone pillar.

The internet as provided by a James Bond villain.

This "floating railway" is one of the world's oldest monorail systems.