At the Harbour School in Hong Kong, Cesar Harada teaches citizen science and invention to the next generation of environmentalists. He's moved his classroom into an industrial mega-space where imaginative kids work with wood, metal, chemistry, biology, optics and, occasionally, power tools to create solutions to the threats facing the world's oceans. There, he instills a universal lesson that his own parents taught him at a young age: "You can make a mess, but you have to clean up after yourself."