If you don't mind stretching things a bit, a horse or any other animal used to pull human-made vehicles is a sort of living engine. Our species has been using them forever, and we still do, despite ...

Standing on the marina, Rob Skelly peers into the darkness of the river where bright speckles of algae drift in the water. A neon green invader. “It’s starting to build,” he says. “Tomorrow, you’ll ...