Fireflies are disappearing — and most people don't know it. Light pollution, pesticides, and loss of habitat are extinguishing the summer light show that defined childhood evenings for generations. Fireflies need tall grass, leaf litter, and dark nights to mate and lay eggs. The simplest thing you can do: turn off outdoor lights after dark, leave a wild corner of your yard unmowed, and skip the pesticides. A little less tidy, a lot more magic.