The world's largest wooden structure.

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

One of the few remaining ancient aqueducts described by Frontinus as 'the most solemn testimony of the Empire.'

Natural stone arches form a walkable "cathedral" at low tide, then disappear entirely when the water returns.

Spanning the El Chorro gorge, this pathway used to be one of the most dangerous crossings in the world.

An enchanting monastery in the Spanish countryside appears lifted from a fantasy tale.

Three bridges and one giant canyon make up this fantastic Spanish settlement.

These Stolpersteine located in Spain honor Republican soldiers who perished at the hands of Nazis after the fall of France.

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

This alley in downtown Chicago held the bodies of over 600 people after the fateful Iroquois Theatre fire.