A historic 1890s architectural masterpiece with an iconic clock tower that, once open to the public, now faces an uncertain future.

An uber-secure, windowless tower of doom in the center of Manhattan is an NSA spyscraper.

Try not to get slimed in Tribeca.

A crumbling hospital from the 1850s on Roosevelt Island.

Tucked in the back of this amazing antique store is an important piece of medical history.

New York City's only preserved family home from the 19th century.

The site of the deadly Triangle Shirtwaist Factory Fire.

A terrific purveyor of natural history objects and curios.

Sweden's oldest animated sign is still lighting up the skyline today.

This homeless brass fox tugs at your heartstrings from the foot of a Stockholm bridge.

It houses the remains of a 17th-century version of the Titanic.

Beneath Denmark's Højbro bridge, a bronze merman and his seven sons forever mourn for the mother and wife who left them for land.

Museum on earth sciences featuring a recreation of a famous curiosity cabinet.

Copenhagen's celebrated theme park and gardens.

Danish tourist destination well known for open stalls where vendors sell marijuana on the street.

The old observatory in Copenhagen has a spiral corridor used as a racetrack.

A tiny museum housed in a New York freight elevator specializes in the "overlooked, dismissed, or ignored."

An artist's cute bronze subway sculptures belie his violent artistic past.