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

Established in 1638 to battle the Black Death, Hortus Botanicus Amsterdam is a treasure trove of rare flora.

A curious collection dedicated to human and animal anatomy and pathology.

The world's first zoo for microbes collecting the horrible and wonderful things living on and around us.

Museum preserving torture methods from the past.

This gaping hole in the middle of a remote mountain lake looks like a portal to another dimension.

The studio of Catalonia's most famous theatrical designer remains exactly as he left it.

The 2,000-year-old Roman columns are hidden within Barcelona's Gothic Quarter.

Step inside the first house designed by Catalan architect Antoni Gaudí, considered to be one of the first Art Nouveau buildings.

Gaudí's famously flamboyant architectural style is on full display in this sprawling park and garden.

One of Antoni Gaudí's most classic buildings is well-known for its "dragon-back" design.

This semi-secret storybook hedge maze is also the oldest garden in the city.

Gaze upon chocolate sculptures depicting everything from chariot races to Gaudí's famous church at this shrine to sweets.

An unusual stroll through gentlemen's erotica demonstrates that pornography is timeless.

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

Most prolific publishing house in the 1600s open to the public.

One of the smallest bookstores on the planet.