 The first hour of a special two-hour Modern Marvels takes a close look at the technologies that could doom the human race... or save it. Threats include runaway global warming brought on by the burning of fossil fuels; global nuclear war triggered by the deteriorating Russian nuclear command and control ; a global collapse caused by the abrupt end of the oil economy; and even nanotechnology gone awry. Technological solutions include renewable energy breakthroughs including the latest in wind and solar, and the high-tech world of dismantling and monitoring nuclear weapons.