There's a labyrinth of manmade tunnels stretching for over an acre beneath Bristol.

17th-century merchants in Bristol nailed their deals by placing money on these pedestals.

One of Bristol's best-hidden gems has ties to Lord Byron, whence it became the nation's first reformatory school for girls.

The Bristol Camera Obscura housed in an ancient windmill.

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

Berlin's natural history museum houses the world's largest mounted dinosaur and the late beloved polar bear Knut.

The most visited, and possibly most controversial, museum in Germany.

Beneath the impressive baroque cathedral that rises from the center of Berlin lies the largest collection of Prussian royals in the world.

The largest free-standing aquarium in the world resides in a hotel lobby in Berlin.

A surreal museum of extraordinary industrial objects.

A medieval weapon rumored to have been used by the brilliant poet himself.

A slightly creepy gallery of plaster cast models in the same museum as Michelangelo's David.

The oldest operating pharmacy in the world features 800-year-old recipes.

The famous sculptor left his mark on this Italian wall in an internationally protected example of street art.

Secret refuge and museum of the Duke of Florence.

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

The middle finger of modernity.

The largest and most famous wax anatomical collection anywhere in the world.

A hospital where antique dolls are given new life.

A collection of objects supposedly singed by the hands of souls in purgatory.

At the crypt of St. Mary of Eulogies and the Dead you are left alone to ponder mortality among piles of skulls.

This hidden Art Nouveau courtyard is an opulent feast for the eyes.

A treasure trove of Renaissance-era funerary art in a Roman church built on top of Nero's grave.

The former home of an Italian artist is now a shrine to his ambitious works.