Across the world, historic buildings of all kinds conceal hidden corridors leading to separate annexes, wings, and even different properties altogether. The reasons these secret passageways were first installed are equally as interesting as the corridors themselves. Some were nothing more than the follies and quirks of wealthy property owners, while others were necessary to maintain the safety of those who lived or worked there. Take a look at the stories behind six fascinating secret passageways that exist around the world, from the Vatican to the pyramids of Egypt.