East About to be Overrun by Billions of Cicadas

Any day now, billions of cicadas with bulging red eyes will creep out of the ground and overrun parts of the East Coast.

But don't worry. They don't do any harm. It's an event that occurs in the region just once every 17 years. The bugs have been underground since 1996, feeding on tree roots.

Once the ground is precisely 64 degrees, they will crawl out, and eventually shed their outer skin to emerge with wings. Then they will make a lot of noise, mate and die. And their offspring will burrow back into the ground to start the 17-year cycle all over again.

It's not clear how the insects get their timing just right.