Secret passages, mysterious tunnels, and hidden rooms are everywhere, you just have to know how to find them.
10 Amazing Secret Passages, Tunnels, and Mysterious Hidden Rooms - From the Underground Railroad to Pixar, here's some past and current places created to get out of sight.
Mysterious Architecture: Secret Passages & Hidden Rooms in Castles and Palaces - Most castles have hidden ways and secret escape routes.
Hogwarts Secret Passages - Harry and his friends often got around by hidden ways. And, it's not just Hogwarts, either. Secret passageways are regulars in novels. Check out: The Most Magical Doorways in Literature.
31 Beautiful Hidden Rooms And Secret Passages - Want a hidden room or secret passage in your own home? Here's some ideas. Or, here's an additional 16 Houses With Cool Hidden Rooms.