If you ever wanted to know how Canon make their lenses you now have a great opportunity.
Canon has created a Virtual Lens Plant with lots of information about their lenses.
You can navigate through the factory and see the several process that the lens have to pass before they reach your hands.
From Material Processing (Material Blending, Pre-Fusing, Fusing/Cooling, Quality Inspection, Press/Forming and Annealing), Lens Machining (Rough Grinding, Fine Grinding, Polishing,Inspection, Alignment and Coating) to Lens Assembly (Assembly1 - front Unit, Asembly2 - Back Unit and Comprehensive Inspection Completion) you got it all.
You can see all these stages on small videos instructional videos.
And last but not least you can also check the Lens Gallery and take a look at some of the most used types and features of the nowadays lens coatings and materials.
From the Optical Glass Lens, Ultra Low Dispersion Lens, Fluorite Lens and Spherical/Aspherical Lens and also come with small videos.
I think that after you look at all the website in the end you will know a lot more about your lenses and why they are so expensive :)