What do the colors on Flags stand for?

How was the American Flag designed? What does Flag Day celebrate? Why are Flags rectangular? Thank you for being a Who Smarted + Subscriber! Get official Who Smarted? Merch: tee-shirts, mugs, hoodies and more, at Who Smarted? For more information about our other projects, including bespoke branded podcasts and series for your company, check out  Atomic Entertainment.