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

The monumental home of Prussia’s eccentric "Cannon King."

This shuttered power plant is now Turkey's first industrial archaeology museum.

An abandoned 19th-century iron factory perched along the outskirts of an idyllic village.

Tourists often confuse this beautifully ornate former cigarette factory for a mosque.

Dubbed "Wistom" by locals, this abandoned factory is an urban explorer's dream.

The seawater playground of gilded-era San Francisco burned to the ground in 1966.

Hidden in plain sight on the Hudson River is an abandoned train station where nature has taken over.

The world's only three-story rotary jail is now a museum to a bizarre trend in prison design.

38-story baroque tower reflecting Detroit's rise, fall, and possible rise again.

The home of aviation trailblazers, in a remote corner of the big city.

A treasure trove of artifacts, books, and artwork from the "golden age" of exploration.

Dr. Strangelove-esque tours reveal the inside a bunker once reserved for Stalin himself.

A marvel of technology a century ago, this disused power station now offers a lovely glimpse into the industrial design of the past.

Abandoned Nazi train station turned underground astroparticle laboratory.

To truly appreciate Detroit's landmark skyscraper, you have to step inside.

Berlin's old airport.

A beautifully eclectic mix of architectural styles.

An abandoned NSA listening post on Berlin's "Devil's Mountain."

The ruined remains of the airport Claus von Stauffenberg departed in his failed attempt to kill Adolf Hitler.