A stunning, abandoned limestone quarry in southern Indiana provided the stone to erect the Empire State Building.

Tour the world's largest deep-hole dimension granite quarry, where you can view the plant where gravestones are made and roll a ball down the outdoor granite bowling alley.

One of the largest burial mounds in the Netherlands and Belgium.

This 1920s Amsterdam neighborhood was built as a giant experiment in concrete construction.

Devious political maneuvering and four ancient, working telescopes are central to the world's second-oldest observatory.

This still-celebrated home was a radical architectural experiment in 3D De Stijl.

Peek through a transparent pyramid and drink in the mountain made of books.

Survival capsules find a second life as a unique hotel.

A miniature city, once ruled by the Queen of the Netherlands.

Hidden within a Netherlands crater is a stone bed that lets those who lie in it see the sky as a curved surface.

Strange secondhand shop showcasing taxidermy and oddies

A preserved building where the dead were once watched for signs of life.

The only museum of sake in the United States is nestled in an unlikely California college town.

Ever wanted to can Spam?

A museum dedicated to a Cold War era sausage.

Now an entertainment complex, the Lingotto building was once an avant-garde auto factory with a test track on the roof.

When this funny little building went up in the 19th century, most people thought it would simply fall over.

Cliffside houses provide a spectacular view from their perch above the valley.

Abandoned for decades, trains still pass through the now-restored remains of one of Madrid's first metro stations.

A former steam-powered mill from the 1800s is now an industrial park with a giant steel dragon slide.

A remnant from the golden age of aviation still in use today, Pan Am's Clipper service took off from this Art Deco gem.

Located in the thermoelectric factory that once powered the entire city, this Portuguese museum is shockingly fascinating.

The former home of a trailblazing surrealist is still filled with haunting dolls and grim paintings.

This historic hydroelectric power plant in Japan has been preserved and is open to the public.