This empty Detroit high school was too expensive to maintain or destroy.

Unique Michigan homes look like something out of Tolkien's "The Lord of the Rings."

Former self-sufficient mental institution now a planned community.

A subterranean world of tunnels links several buildings of this rare 19th-century asylum.

A botanically themed auditorium blooms within the world’s last operating double-decker theater.

A lonely beacon, precariously perched atop a remote sliver of rock.

This meticulously extracted nervous system allegedly came from a 19th-century custodian who donated her body to science.

Tiny horses tethered to antique rings are scattered around the city.

The palace window through which Protestant nobles flung two Catholic regents, thus sparking the Thirty Years' War.

Someone left a Boeing 737 in a field in southern Bali.

Long-forgotten artifacts give incredible insight into New York's most glamorous hotel.

The world’s largest Masonic temple was saved by the White Stripes.

The remains of the oldest synagogue in Britain lay forgotten for seven centuries, hidden under a humble shop.

An Art Nouveau gem hides beneath the layers of city grime obscuring this once-magnificent building.

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

The weathered grave of a medieval anchoress who walled herself up in a cell attached to a church.

Thousands of flowers create enchanting pink tunnels over the city streets.

Now abandoned, the first public health hospital in the U.S. saw more than one million immigrants from around the world.

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

A 16th-century fountain marks the site of a lost medieval cemetery once filled with mass graves.

Twice a day a speeding train passes only inches from the homes of this residential neighborhood.

Woven tree art gives this towering Australian woodland a touch of mystical whimsy.

19th-century scientists would make the pilgrimage here to verify the precision of their measuring sticks.

A Swiss board game museum housed inside a picture-perfect castle.