This spring, parts of the East Coast will turn squishy and crunchy -- the return of the 17-year cicadas means surfaces in certain locations (in patches from VA to CT) will once again be coated in bugs buzzing at 7 kilohertz. In their honor, we're rebroadcasting one of our favorite episodes: Emergence.

In this classic hour, we take a look at the bottom-up logic of cities, Google, and even our very own brains ... with fire-flyologists, ant experts, neurologists, a mathematician, and an economist.

We'll be back next week with a brand-new hour. In the meantime, enjoy Emergence, and consider rolling up your sleeves for some DIY bug science: help us track the return of the Magicicada Brood II.