A Hawaiian stairway to heaven—that you can't climb.

HBO series' stage tucked away in a Greenpoint lot is the largest theatrical set of its kind in the United States.

A wooden hut from the Heroic Age of Antarctic Exploration.

Hungarian self-built castle.

The 606 is a decade in the making.

Modern Japanese museum is buried by snow annually.

An ancient monastery, a locked room, and a mysterious book heist.

The Bristol Camera Obscura housed in an ancient windmill.

A Gothic cathedral created from volcanic rocks.

A thin pane of glass keeps visitors from sliding off this futuristic skywalk.

A beautiful and abandoned New York subway station from 1904, complete with chandelier.

A castle from the Holy Roman Empire that hosts traveling youth... in its stables.

An eccentric inventor's castle home with its own indoor weather system.

Quirky Welsh observatory unites art and science.

One of the Seven Wonders of the Modern World holds the world's tallest metal staircase.

A castle built by an eccentric medieval enthusiast in suburban Ohio.

This bridge was constructed from the rubble of the infamous Bastille.

An architect's childhood fantasy treehouse made real.

A corkscrew-shaped barn in Ireland.

Abandoned railway line circling the city of Paris.

The Pope’s secret escape route.

One of the first skyscrapers in Santa Monica, and a famous getaway for the Hollywood elite of then and now.

These mansions date back to Chicago's days as a brewer's paradise.

The Art Deco Silver Screen.