With stunning footage and cutting-edge technology, National Geographic explores the human body from the inside out as never before. In four classic programs, we'll look how our incredible human machine works-from the miraculous in-utero development of a fetus to the mechanics of a beating heart, and from the formation of skin to the amazing way our complicated systems work together for sensing, adapting, reproducing, regenerating, and thinking. Programs include How to Build a Beating Heart, Skin, In the Womb, and Incredible Human Machine.