For two thousand years, cadavers have been involved in science's boldest strides and weirdest undertakings. They've tested France's first guillotines, ridden the NASA Space Shuttle, been crucified in a Parisian laboratory to test the authenticity of the Shroud of Turin, and helped solve the mystery of TWA Flight 800. For every new surgical procedure, from heart transplants to gender reassignment surgery, cadavers have been there alongside surgeons, making history in their quiet way.