From designer's website at Numenera.com:
Numenera is a science fantasy roleplaying game set in the far distant future. Humanity lives amid the remnants of eight great civilizations that have risen and fallen on Earth. These are the people of the Ninth World. This new world is filled with remnants of all the former worlds: bits of nanotechnology, the dataweb threaded among still-orbiting satellites, bio-engineered creatures, and myriad strange and wondrous devices. These remnants have become known as the numenera.
Player characters explore this world of mystery and danger to find these leftover artifacts of the past, not to dwell upon the old ways, but to help forge their new destinies, utilizing the so-called magic of the past to create a promising future.