What is the mantle and why do we want to get our hands on it so badly? On this first episode we talk to chief scientist Henry Dick and staff scientist Peter Blum about the history leading up to expedition 360 and what we might learn from the next two months.

Correction: this episode incorrectly states that seismic waves travel faster in denser rocks. The correct relationship is seismic waves travel faster in stiffer (more rigid and incompressible) rocks.