Ray Harryhausen was a genius and his talent is directly responsible for many of the cool effects you see in movies and on TV today. io9 recently posted a fantastic collection of photographs of the stop-motion special effects pioneer, that show him working with his models.
Harryhausen was behind movies like Mighty Joe Young, Jason and the Argonauts, and Clash of the Titans. His on screen magic was and is amazing to see, and so are these images which show him hard at work.
Mighty Joe Young 1949
7th Voyage of Sinbad 1958
Animating a skeleton from Jason and the Argonauts 1963
Clash of the Titans 1981