Three floors of musical instruments coming from all corners of the world and hundreds of years of musical history.

This collection of lurid religious statues tell the tales of a saint who stood down the devil.

Each spring, a dreamlike carpet of bluebells overtakes the forest floor.

These ancient artifacts are a testament to the enduring significance of the bull in Spanish culture.

The abandoned funicular tunnel was a secret base for the BBC during World War II.

A subterranean ice warehouse that has lain hidden beneath central London for over a century is now open to the public.

17th century streets hidden under Edinburgh were once a breeding ground for the black death.

Neon artworks light up this dark Edinburgh tunnel.

This series of Scottish caves has no clear purpose other than baffling historians.

The red letters in the literary pavement leading to the library form a mysterious code.

A 400-year-old mummified arm dangles from the ceiling of St. James the Greater, serving as a warning to thieves.

The history of occult science is turned into a creepshow at this lurid Prague tourist attraction.

This spooky statue sits outside a famous Prague theater.

Synagogue built from the stones of Solomon's temple contains the golem of Prague.

An extraordinary collection of 18th century anatomical waxworks.

These slanted cubic abodes are a creative if odd solution to a zoning pickle.

Rare wooden escalators lead deep down into an otherwise staggeringly monotonous tiled tunnel.

A vast Communist-era exhibition space in the Bulgarian capital.

England's largest white horse isn't even white.

The largest cave chamber in Britain—big enough to fit a whole cathedral inside.

One of the oldest and certainly best preserved Cistercian abbeys still in existence.

A tree planted by Marie Curie is treasured by the Radium institute that she set up.

A program of Communist glamour in post-Stalin Poland is preserved in this colorful museum.

This tri-part waterfall is a little bit of fairytale beauty in the heart of Luxembourg's Little Switzerland.