Clap your hands at the base of the pyramid, and the song of a sacred Mayan bird will echo through the air.

Disused penal colony features prisoner artwork, some sketched in human blood.

A secret climbing tree hides along the side of a Costa Rican road.

This Costa Rican topiary park is a surreal garden of unearthly delights.

This former abandoned hospital, a complex of stunning 19th century buildings, once housed 2,000 psychiatric patients.

A deserted 20-lane highway runs through Myanmar's empty capital city.

This derelict superstructure was a very important warning system for the Soviet military.

Over 2,000 ancient temples dot the Myanmar landscape at the site of this famed archaeological site.

This unique temple complex remains off the typical tourist trail.

An eerie, derelict amusement park in Berlin.

This hidden fortress has been coined the "City of Ghosts."