We were just driving in Lycoming County, Pennsylvania near the town of Allenwood when we heard a cacophony outside, apparently coming from the trees. It was loud enough to hear with the car windows rolled up. Then I saw some of the noisy culprits flying in the road. They were large, thumb-sized insects with bright red eyes. I knew immediately we had encountered periodical cicadas.
I'm sure many people drove right on by without realizing that they were seeing insects that had spent their lives underground since 1991! Isn't that amazing?
For more information, see this Penn State Fact Sheet.