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

Terrifying derelict military hospital once housed a recuperating Hitler.

Stunning Roman aqueduct used for 1900 years and still standing.

A Romanesque tower appears when water levels drop.

The Gaudí-inspired building that was the start of Terrassenc modernism.

An architect transformed this abandoned cement factory into his castle-like workshop.

For one day every month Barcelona's Estació de França transforms into a market for model trains.

A massive forgotten storehouse from 1913 on the Brooklyn Waterfront has a spectacular view of Brooklyn.

Neon signs that grace the windows of Bergdorf Goodman's and Tiffany & Co. come from this studio in Brooklyn.

Tucked in a nondescript downtown Brooklyn mall is a bar containing a remarkable turn of the century anatomical wax collection last seen in 1920s Berlin.

Detailed facade of a brownstone in Boerum Hill.

The world's northernmost aquarium looks like it has fallen over.

Longest road tunnel in the world features an air treatment plant and the illusion of daylight.

Stay overnight in the world's most sleekly designed rabbit hole, free of charge.

A stunning silver lining to global warming's gloomy cloud.

This giant boulder is pinched over a 1000-meter abyss by two mountains.

Walk 2,300 feet above the ground on the "Troll's Tongue."

A subterranean house of worship carved right out of the bedrock.

A million and a half tons of earth were used to create one of the world's largest land sculptures.

A locomotive made from 185,000 bricks celebrates the town's pioneering railway history.

A rococo retro-futurist future-rustic vernacular between yesterday’s tomorrow and the future that never was.

This decrepit abandoned building is made all the more eerie by its dark history.

Second largest wastewater treatment plant in the country.

The watery grave of an impractical idea.