Behind every line on a graph, there lies an extraordinary human story. Mathematician Hannah Fry is here to tell us ten of them.

There is a bizarre number in maths referred to simply as ‘i’. It appears to break the rules of arithmetic - but turns out to be utterly essential for applications across engineering and physics. We’re talking about the square root of -1. WHICH MAKES NO SENSE. Professor Fry waxes lyrical about...