A whimsical and twisted animatronic monster tour beneath the streets of Berlin.

Infamous and now demolished panopticon prison built by its former inhabitants.

Sometimes called the Banksy of Madrid, Muelle was a pioneer of street art in the Spanish city.

The remains of this misplaced church were moved here stone by stone.

These abandoned country fairgrounds are filled with replicas of Spanish monuments.

Replicas of fossils unearthed during renovation work reveal how this area would have looked millions of years ago.

A vault of safe-deposit boxes in an old bank has been repurposed as a time capsule of Hispanic culture.

Remains of the lost church hide beneath this Spanish Parliament building.

A reproduction of the famous prehistoric cave paintings is hidden underground at the National Archaeological Museum.

Part of the medieval watchtower is displayed in an otherwise ordinary parking garage.

The remains of the second-oldest zoo in Europe can be seen within these library gardens.

This small museum tucked within a subway station holds pieces from Madrid's past.

The lengthy skeleton of one of the tallest Spaniards of all time is on display in Madrid.

Just like in Hollywood, Madrid has also a forgotten walk of fame.

A subterranean relic of the Spanish Civil War hides below this picturesque park.

Among the oldest structures in Madrid, these Moorish walls once guarded the medieval city of Mayrit.

This funky former tobacco factory is one of the most striking examples of Madrid's cultural diversity.

One of the world's oldest universities houses an incredible collection of anatomical models, mummified body parts, and human bones.

In the fictional world of Kcymaerxthaere, celestial wonders marked a portal to a powerful route of travel at this site in Madrid, Spain.

The little church's beautifully frescoed ceiling has earned it the nickname “the Sistine Chapel of Madrid.”

This macabre masterpiece of a mural is one of Francisco Goya's "Black Paintings."

The earliest known map to show America, discovered by accident at a Paris bookshop.

This amazing abuela became a diehard metal fan late in life and an icon of Madrid's '80s rock scene.

Over two centuries old and counting, Madrid's massive botanical garden contains one of Europe's only desert environments.