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

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

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

The crypts of Capuchin friars decorated with the bones of over 4,000 friars, including an entire "crypt of pelvises."

Elaborately carved to showcase the glorious wealth that the age of exploration brought to the Portuguese empire.

Whether they are bulls or pigs, these ancient animal sculptures are fascinating relics.

A huge cathedral single-handedly constructed by one eccentric monk.

Geological storytelling.

Remarkably intact Roman stone fortifications have encircled this Spanish city for centuries.

Eight naturally mummified bodies in glass coffins are housed in an underground crypt.

Crushed coral and crystals give the sand its signature coloration.

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

The now-abandoned tunnels were built for the transcontinental railroad on the route where the first wagon train entered California.

A marble Lucifer hides behind the pulpit of this Gothic cathedral.

A deadly ancient portal to the underworld.

Rebuilt remains of a temple to Roman god Mithras.

The underground sanctuary of a mysterious ancient cult.

A serene garden path lined with 36 haiku stamped into clay stones.

The yawning maw of this pagan visage is said to bite off the hands of liars.

The ruins of the "20-year town" lay out among the mountains of Alberta.

This Old West eatery along America's Loneliest Road was originally a stop on the Pony Express.

The site of a mysterious pony massacre is rich with extraterrestrial conspiracy theories.

The Denver airport is guarded by a 32-foot-tall sculpture of a demonic horse.

Taxidermy of the racing horse with a huge heart, who inspired hope in the Depression.