Abandoned Nazi train station turned underground astroparticle laboratory.

Considered the birthplace of the Copper Age and Bronze Age, the river is tinted red from 5,000 years of mining.

The morbid items in this small and hidden museum are not for the weak stomached.

The world's largest wooden structure.

A Spanish town built into the cliffs.

These magnificent city walls rise from the barren sun-baked Spanish plains like something straight out of a fairytale.

This house's itty bitty size means no humans allowed.

This Funeral Hearse Museum represents the finest in cadaver transportation.

A gravity-defying "devil's bridge" that has a surprising architectural feature for its stability.

A landscape decorated with enormous skull sculptures.

Giant eggs, walls of bread, and nightmare surreality mark the largest collection of works by Salvador Dalí.

At the foot of a waterfall lies a peaceful swimming lagoon and evidence of over 60,000 years of human habitation.

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

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

Commonly acknowledged as the only public monument to the Devil himself.

The largest Art Nouveau complex in the world is a Barcelona hospital with a 600-year-long history.

Bacteria and algae give the salty water its bubblegum hue.

Wonderland replication in progress by one persistent man.

Bask in the 19th century grandeur of an eccentric Freemason millionaire's private gardens.

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

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.

This cemetery features modernist statues as strange as its name.

A beautiful but toxic fountain of mercury.