Numenera is set a billion years in the future. Eight great civilizations have risen and fallen on Earth. Even though the current inhabitants live at about a medieval level of technology, the leftover remnants of these ancient advanced societies lie all around them. Some of these are extremely helpful: advanced tools, valuable means of communication and learning, transportation, defenses, and weapons. Others are dangerous: genetically altered monstrosities, flesh-warping radiation, creatures transplanted from distant stars, and clouds of out-of-control nanobots, just to name a few.