If you had to define a bridge, it would probably be something like "a structure spanning and providing passage over an obstacle" (slightly abrided from dictionary.com, that one). But what about a structure that provides passage above an obstacle ... but not actually over it?
Not sure what that means in practice? Well, Deputy Dog has the answer with a delightful set of six bridges-to-nowhere that take people out into mid-air, and no further. These include the astonishing Grand Canyon Skywalk; viewing platforms in the mountains of Italy, Switzerland and Austria; and Norway's design-conscious but frankly terrifying Aurland Lookout (pictured, photo courtesy of Lewis Martin).
Pontists may also be interested in another recent Deputy Dog post on the use of rockets to build a suspension bridge.