S2, E3: England 1666. A great fire engulfs the city of London, devastating everything in its path, including the magnificent Gothic cathedral of Old St Paul's. Christopher Wren's dream is to raise a new cathedral from the ashes, the centre piece of a city set to rival the grandeur of Ancient Rome. With a mathematician's belief in the inherent superiority of Classical architecture, Wren wants to create England's first Baroque cathedral, crowned by a great dome. But even before the first stone is laid, he faces unprecedented challenges. Through a mixture of defiance, cunning and engineering brilliance, Wren sets out to realise his vision. And 36 years later, the Phoenix of St Paul's rises from the ashes of the Great Fire to become an iconic landmark of London.