Photographed from an ultra-light plane last December, these whooping cranes are being taught to fly south for the winter. Almost completely wiped out by 1940, there are now 536 known captive and wild whooping cranes in North America. But those raised in captivity will not migrate to warmer climes automatically -- they have to learn the skill.
Five amazing, clean technologies that will set us free, in this month's energy-focused issue. Also: how to build a better bomb detector, the robotic toys that are raising your children, a human catapult, the world's smallest arcade, and much more.