est110590: Not exactly a secret passage, but still a pretty cool setup. A similar glass bottomed pool could be used in other stealthy applications.
(via fuckyeahbookshelves) Beautiful library
Derelict Bank Vault
Hidden drawers in steps
Old bank vault
Security glass advertisement – filled with cash. There was a security guard close by in case of someone doing something dramatic, like attempting to run over entire display with a large vehicle.
Underground tunnel connecting monolithic domes.
Secret tunnel – Mt. Rushmore’s Hall of Records – This entrance to the hall in the canyon behind the presidents’ heads was carved in 1938 by the original designer of Mt. Rushmore, Gutzon Borglum. However, the project was halted in 1941 when Borglum died in a minor surgery. But in 1998, the National Park System […]