Going wild. We don't see it as a good thing. And why would we? For most of our time on earth, humanity has been running from lions and other wilderness dangers. We've worked hard to make our local landscapes as safe and convenient as possible. Sometimes that's meant paving over areas that might burst into weeds. Other times, we've dammed rivers for electricity or irrigation. But now pollution, climate change and disruptions to the water cycle are affecting the world in ways we never anticipated. What if the new key to making our lives safer (and even healthier) is to allow the wilderness back into our cities?