A makeshift shrine to the late rock star is still kept up on the nondescript façade outside 1 Logan Place.

Stunning Roman aqueduct used for 1900 years and still standing.

A signal indicates the entrance to this alley, rumored to be a meeting place for witches.

This ancient Spanish castle sits high upon a hilltop.

Super Robot anime statue guards a forgotten suburban development in Tarragona.

Hidden well off the beaten path in Catalonia is this crumbling medieval castle that is slowly being covered in graffiti.

An ornate tower shows off a local artist's architectural flair.

This whimsical winery by Antoni Gaudí looks ripped from the pages of a fairytale.

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

The abandoned ruins of a beautiful medieval castle just outside Barcelona.

One of Europe's largest supercomputers is housed inside of a disused chapel.

This cemetery features modernist statues as strange as its name.

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

An early 20th-century bullring converted into a modern shopping center.

One of the most photographed buildings in a city known for its Modernista architecture is an abandoned squat.

A bookstore dedicated to the intersection of comedy and art.

Hidden in a secluded Greek cove is a pristine beach marred only by the rusting smuggler's hulk stranded on its shores.

The hallucinogenic center of the ancient world.

An islet filled with wooden houses where the open sea meets a lagoon.

Ancient Greek oracle of the dead.

One of the most photographed locations in the entire city.

One of the largest single-span stone-arch bridges in the Balkans looks like something straight out of a fairytale.

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

A peculiar mansion built by the troubled heir to the Winchester Rifle Company fortune.