Military weaponry, the natural world, anatomy, mathematics, geometry and flight - just some of the subjects which fascinated the mind of Leonardo da Vinci. His notebooks remain testament to his endless investigations and experiments, evidence of a life of constant searching to discover more of the world around him. He was forever extending the parameters of human possibilities.

So what made Leonardo unique and what other areas absorbed him? Here four Leonardo experts examine some of the projects and issues which engaged him and look at the world which surrounded him in Renaissance Italy.