Meant to resemble a massive tree, the building is the best example of Spanish organicist architecture in Madrid.

Built to celebrate the glory of a new queen, this forgotten monument has moved around Madrid three times, reflecting 200 years of political whims and city redevelopment.

The only urban monument in the world designed by the great surrealist painter Salvador Dalí.

Madrid's romantically ornate crystal palace has been offering shelter to plants and art for over a century.

Abandoned for decades, trains still pass through the now-restored remains of one of Madrid's first metro stations.

A lush indoor jungle fills this bustling Madrid transportation hub.

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

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.

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

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

In this brilliant blue spring in Germany, legend has it that a sad mermaid learned to finally laugh.

Held in an old church, this clockwork museum maintains a special focus on titanic tower timepieces.

A small but immensely extravagant palace built by the "Night King."

The stones of this formerly witch-obsessed castle were used to build a church.

Walk inside a half mile long crevice right outside the town of Garmisch Partenkirchen.

A beautiful gorge filled with streams and waterfalls.

The fairy tale castle of the "fairy-tale king."

This Rococo church is known as the most beautiful village church in the world, and does not disappoint.

A striking 12th-century-style castle built on the edge of a cliff.

An old slaughterhouse now holds the largest collection of pig artifacts.

This natural hill rose another 130 feet from the debris and rubble added after World War II.

This old wooden funicular railway leads to a cemetery in the forest.

Remnants of a cone-shaped Nazi bomb shelter.