A place to eat for on-the-run agents and espionage enthusiasts.

This lab's maddening silence is good for business but bad for sanity.

When Croatia became independent of Yugoslavia, the splintering governments left behind these concrete tunnels.

An ethereal glowing blue ocean cave in Croatia.

Large, airy hallways hide within an impenetrable fortress that beckons urban explorers.

A wonderfully strange collection of 500+ stuffed frogs doing people things.

When a supermarket opened up shop within a medieval building it became protected by UNESCO on a technicality.

The building was originally a gas station built to resemble a Japanese tea house.

Legend says Dungeons and Dragons players can get their dice blessed at the creator of the game's memorial.

A statue honors the genius who allegedly first took a meatball and made it into a hamburger.

A wonderfully curated used bookstore in an airport.

According to the legend, this strikingly beautiful hill has miraculous healing powers.

Built in 1933, this unique ballroom is nicknamed the "floating dance floor."

The oldest continuously-operating tavern in Wisconsin used a clever loophole to serve alcohol during Prohibition.

This circus town museum recognizes the outstanding clowns of history.

This unique zoo is the only place in the world where you can see all 15 species of crane.

This forgotten beach house built to look like a Frank Lloyd Wright masterpiece overlooks a hidden beach.

Small-town museum dedicated to outer space ... and bicycles.

A unique botanical garden housed in three giant geodesic domes.

A circus of light and sound forms a sensory ode to an iconic train that will never pass through town again.

A town filled with hot chocolate, dazzling lights, and lots of Christmas cheer.

The spaceship-like theater, which is still in use, was one of the most popular exhibits at the 1964 New York World's Fair.

This solitary gravestone is separated from the rest in Appleton, explaining why local legends continue to surround it.

A trailblazing sovereign nation tucked in the American state of Wisconsin.