We all know that a billion is a lot and a trillion is a lot more, but what do you call numbers that are even bigger? A Googol is bigger: it's 10 to the hundredth power—but it's not the biggest. In this  well-researched 19 minute film, master explainer Sharkee takes us through ever larger numbers. 

He applies three rules. The largest number cannot be a number plus 1. The number must be useful in some way. And infinity doesn’t count, because it isn't actually a number.