Most of us know pi (π) as an infinite number that plays a crucial role in calculations for circular or spherical objects. But, from the human DNA and the larger cosmos to the way a river snakes its way to the sea, this irrational number can be found all around us. And its mysteries are tough to crack. Did we invent pi? Or does it just happen to exist everywhere? Why can’t we replace it with any other constant? And, more importantly, what is the purpose of this number? Tune in for the absorbing story of pi.