Look -- up in the sky! It's a bird! It's a plane! It's a ...chemtrail? You've probably heard of these allegedly poisonous strips of stuff streaking across the sky, but what are they, exactly? Tune in to learn more in this classic episode.

They don't want you to read our book.: https://static.macmillan.com/static/fib/stuff-you-should-read/

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