 The CrowdScience team loves a challenge, and this week we're tackling questions about flies, including how many flies have ever existed. That's not how many species of fly, but how many individual flies have ever lived in the whole history of planet Earth. Also, why do flies keep flying in circles around my room? And what's the point of flies anyway? I'm Caroline Steele, and that's coming up on CrowdScience after the news.