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

A lush indoor jungle fills this bustling Madrid transportation hub.

This Funeral Hearse Museum represents the finest in cadaver transportation.

This cafe offers a curated collection of treats and tipples made by monks and nuns.

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

Step inside the first house designed by Catalan architect Antoni Gaudí, considered to be one of the first Art Nouveau buildings.

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 cemetery features modernist statues as strange as its name.

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.

This 18th-century project to build the world's tallest gravity dam was never completed.

Not far from Madrid, a set of perfectly preserved trenches date back to the Spanish Civil War.

This Central New York ghost town was once a prosperous railroad community.

The hellish conditions of this abandoned mine that snakes beneath the Pacific Ocean gave it its diabolic name.

Locals visit this abandoned train tunnel where a man took his own life to ask favors of his spirit.

The “City of Stairs” sits high in the Andes, above the world’s largest underground copper mine.

Rows of 19th-century brick ovens used to process coal into coke form the center of a wooded park.

Faces carved into the cliffs create an otherworldly walking trail.

This once-palatial plantation may have been the site where a draft of the Declaration of Independence was written.

Nine of the very few concrete ships ever made in the U.S. are beautifully decaying off a Virginia pier.

The first presidential bomb shelter was located in an old vault under the Treasury, connected to the White House via tunnel.

Once the supplier for noteworthy projects like the National Cathedral, this old brickworks now lies abandoned.

A celebrity from the late Cretaceous period.