Leather is beautiful and luxurious and natural and one of the great materials of the world. However, it's also absolutely disgusting to make. Here's the process of tanning raw hide into high quality leather. You'll see grey goops, a lot of residue, dumps of bizarre liquids and more. Worth it? I guess.
Here are some of the grosser segments (which in turn, are my favourite segments). A lot of is turned into dog food.