The late Maryam Mirzakhani became a national icon in Iran after winning the Fields Medal back in 2014, the first ever woman – and first Iranian – to win this highest honor in mathematics. A new documentary “Secrets of the Surface” tells her story, and I spoke with Maryam’s lifelong friend Roya Beheshti about Maryam’s legacy. | Christiane Amanpour

One of the world’s most prestigious mathematicians has died at the age of 40. Iranian Maryam Mirzakhani is the only woman to win the Fields Medal - known as the “Nobel Prize” of mathematics. | Channel 4 News