These secluded and abandoned anti-aircraft defenses have become one the most scenic viewpoints in Barcelona.

Gaudí's famously flamboyant architectural style is on full display in this sprawling park and garden.

This semi-secret storybook hedge maze is also the oldest garden in the city.

One of Antoni Gaudí's most classic buildings is well-known for its "dragon-back" design.

Construction of Barcelona's iconic (but controversial) church is expected to be completed in 2026—a century after the death of its architect.

The ruins of an abandoned church loom within a picturesque Ukranian village.

The largest catacomb system in the world.

The 20th-century church looks like a rustic version of the Sagrada Familia.

An ancient Roman theatre restored to its former glory in the Spanish city of Cartegena.

An enchanting landscape of ancient sandstone structures eroded into otherworldly shapes.

Bacteria and algae give the salty water its bubblegum hue.

Vibrant street art created with mixed media.

This amazing example of Valencian Art Nouveau looks more like a cathedral than a public market.

Of the many chalices in the running for the Holy Grail, this one in Valencia Cathedral sure looks the part.

This massive fiberglass Gulliver turns every visitor into a Lilliputian.

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

For nearly 2,000 years this church has been waging war on local snakes by importing cats.

Breathtaking Byzantine paintings cover the inside of this 12th-century church.

Ozymandias’ time-keeping temple.

A glacial pothole was once a hideout for a notorious Scottish outlaw.

Dramatic sea stacks adorn the coast of this small village on the Adriatic coast.

This series of Scottish caves has no clear purpose other than baffling historians.

The one-time stronghold of the noble Douglas family, now home to ghost sightings and nesting birds.

Strange rock formations tower above the river that snakes through this enchanting Icelandic canyon.