A once crucial portion of the Long Island railroad still lays abandoned, waiting to be turned into an urban park.

An eccentric playboy's astounding natural history collection.

Whale bones, scrimshaw, and sperm oil make up just a part of this comprehensive collection of whaling history.

This outpost of America's most popular fast-food restaurant is housed inside a palatial mansion.

A 98-room castle in the middle of Toronto that bankrupted a 19th century electricity multimillionaire.

Elevated freight railway turned wildly successful urban park.

Quirky castle designed by the American actor best known for portraying Sherlock Holmes on stage.

An abandoned asylum once on the cutting edge of lobotomies may be reborn as a Christian college.

A ruined mansion hidden in the woods of the Hudson Valley, home of a tragically doomed romance.

A mysterious air force base built to resemble a Long Island fishing village.

This once-grand marvel of engineering is now 41 miles of scenic hiking trail.

Beneath the mossy overgrowth covering this once-sprawling campus lies decades of history and the secrets that come with it.

Read between the lines of the subway map to find the hidden abandoned Civil War fort.

A formerly abandoned mental institute, now back in business.

An abandoned Gold Coast-era mansion once intended for the exiled ruler of Albania, who never arrived.

The site of a tragic massacre that spawned a multimedia franchise.