Once a year, in only a few places in the world, a flash of light illuminates a dark forest and then it goes dark again. It happens again and again, in bursts of 5 to 8 every few seconds, as the rare species of synchronous fireflies light up the sky.
“The tens of thousands of lightning bugs gather in swarms and flash in harmony as the entire forest alternates between light and darkness. “
https://smokymountains.com/park/things-to-do/synchronous-fireflies-smoky-mountains/
www.firefly.org