the
Visible Human Project is an
organization with the stated
goal of "the
creation of complete,
anatomically detailed,
three-dimensional representations of the
normal male and female human bodies."
1
They do this by slicing up frozen human bodies and taking pictures of the cross sections. (the slices are pretty thin; one millimeter for the male, and one third of a millimeter for the female.) The data set for the male is about 15 gigabytes; storing a 2048x1216, 24 bit uncompressed image for each slice gets big, fast!
I believe that the cadavers used in this project were prisoners who were somehow snookered into donating their bodies to science... they're a little chubby though, from what I have seen.
1source: http://www.nlm.nih.gov/research/visible/