Arkansas artist Eugene Sargent was commissioned to make an orrery, a mechanical system that demonstrates the motion of the planets in our solar system. The just-finished device is absolutely marvelous. Make sure you follow the link to see the detail photos. From Sargent's project page:
The 6 planets and sun and moon are made of glazed porcelain… The gears are bronze. I cast the blanks first, cleaned them up in the lathe, and the little milling machine did the rest. The main shaft of the moon drive train rides on 4 sealed bearings. At present, I don't even use CAD software. All G-code was generated by my own C++ programs.