In modern civilization, we're enthralled by the promise of shiny new technologies -- whether it's stuff that's already available, like a mobile phone with more capabilities than a 1980s desktop computer, or just-over-the-horizon wonders, like solar-powered aircraft and moveable buildings constructed of super-lightweight, super-strong carbon nanotubes.
But let's not forget that tomorrow's obsolescent junk is yesterday's amazing new innovation, and that we have a lot of formerly cutting-edge gadgets, equipment, medicines and chemicals lying around. We could just consign them to the recycling plant or the landfill. But since our planet's finite quantities of raw materials are rapidly being used up, wouldn't it make more sense for us to find new uses for old technologies?
Fortunately, some people and organizations, in both the public and private sectors, are doing just that. Here are five examples of programs that are making productive use of our civilization's discards.