This unmarked and unloved Manhattan subway grate created one of the most iconic images in American cinema.

This otherwise innocuous bodega was once the headquarters of the most feared assassin's guild in American history.

This French castle is said to have once held the Holy Grail but is now a gorgeous mountaintop ruin.

The house where the famed outlaw was shot by a dirty coward is now a museum to the criminal's legacy.

These historic buildings once housed the headquarters of one of the most infamous gangs of New York.

This ancient mountain monastery welcomes all manner of faith in an effort to keep Christians in Syria.

This Queens hospital has stood abandoned for almost 20 years after its patients were secretly relocated in the dead of night.

Standing proud atop a Turkish bluff, this Ottoman palace has retained its grandeur despite being abandoned for centuries.

Britain's answer to the NSA is based out of this deliciously-named circular headquarters.

Manhattan and the Bronx have been playing tug-of-war over this former island neighborhood for more than a century.

What was once one of the country's largest confectionary plants is now an abandoned ruin, but is still pretty sweet.

What was once the second largest steel mill in the US is now a sprawling complex of modern ruins.

This ratty natural history collection is a charming relic among a city rushing into modernity.

Hidden within a Netherlands crater is a stone bed that lets those who lie in it see the sky as a curved surface.

A waterfall runs right through the middle of this Taiwanese shrine to the hundreds of workers killed while building a nearby highway.

Hidden away in the city of Madison, Wisconsin is a nearly forgotten home that Frank Lloyd Wright built for a childhood friend.

The mysterious "Candelabra of the Andes" could represent anything from a god's trident to a hallucinogenic plant.

This ancient abandoned church in a remote part of Turkey is in danger of falling over.

This odd Chilean waterfall-cano hotel must be entered via a rope bridge.

This ceremonial mound is one of the first officially recognized Native American historical sites in North Carolina.

This remote Himalayan temple is in danger of being completely washed away by a melting glacier.

This French "sea of rocks" is packed with stunning rock formations and its own medieval castle.

The attic of a four-century-old canal house hides a clandestine church.

The grave of America's 11th president is not in some grand monument but instead it's hidden away on the grounds of the Tennessee Capital.