Brian Cox and Robin Ince slice deep into the lesser-explored world beneath us. To join them on the journey from the crust to the core they are joined by seismologist Ana Ferreira, geologist Chris Jackson and comedian Phil Wang.

School children learn about the make-up of the Earth with an image depicting the Earth's core, mantle and crust layered neatly on top of each other, but is this an oversimplification? Our experts reveal that the Earth's innards are less uniform than we might think and mysteries still abound, including the make-up of some continental-sized blobs deep inside the Earth. We learn about the incredible heat and pressure as we descend and why that has limited how far humans have been able to explore these deep realms first-hand. We explore the chemistry of the interactions between the Earth layers and how they influence the formation of continental plates and volcanoes. Phil has an existential crisis about falling inside gaps between the plates but is reassured his worries are unfounded as Ana explains the latest techniques being used to understand the world deep beneath us.

Producer: Melanie Brown