A retrofuturistic art installation in the Pittsburgh Airport.

This futuristic airport terminal was abandoned for decades before reopening as a hotel—with a vintage plane of its own parked out back.

A dinosaur-laden walking trail outside Singapore's Changi Airport.

Watch butterflies take flight before you fly.

This angular brutalist playground turns playtime into modern art time.

In the loving memory of a tragically deceased role-player this Illinois park is decked out with both dungeons and dragons.

From bench to vandalism to art, this silly prank seat was funny enough to become permanent.

This is not your typical jungle gym.

In this Florida couple's cottage, nearly every surface—inside and out—is covered in mosaic artwork.

Hidden in an Italian forest is a completely homemade amusement park that has taken a lifetime to create.

A playground built by the kids that is a child's wonderland, and a helicopter parent's nightmare.

Concrete igloos standing across from what remains of the Michigan Central train depot.

This overlooked street light once served as a KGB dead letter box.

A top secret Cold War bunker hidden beneath a Latvian spa facility is now open for tours.

A retail shop has preserved the 17th-century food cellar from the old building it now occupies.

A hidden passageway now marks the site of an assassination attempt on Ronald Reagan that some say broke a 140-year-old curse.

Wading through a small lagoon reveals a secret, wild stretch of pristine beach.

Diego Rivera hid various people and symbols in his first large-scale mural project.

An unassuming house in Wisconsin hides a transient artist’s magnum opus.

A small horde of mythical creatures lurk almost imperceptibly within the museum's wildlife dioramas.

Reproductions of nine banned oil paintings coyly hidden behind a curtain in a New Mexico conference room.

A Texas-sized particle collider that was abandoned due to its Texas-sized budget.

Lost subway station nestled beneath Toronto's busy commuter line.

The narrow mountain road that carves a path between Florence and Victor is tied to ghost towns and ghost stories.