During the summer, billions of bugs travel through the sky. They soar across invisible highways, thousands of feet above our heads—but in the video above, NPR science correspondent and Radiolab co-host Robert Krulwich provides us with an up-close look at the critters. Learn why they fly so high, what happens when the insects reach their final destination, and which bug was once spotted flying 19,000 feet above the ground. 

[h/t The Kid Should See This]

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