To celebrate 80 years of manufacturing lenses, Nikon have recently released a showing how their lenses are made. I thought members of the forum may be interested.

NIKKOR 80th Anniversary Special Movie - YouTube

So as not to offend anyone, I thought I would include the canon version as well. This is a bit more comprehensive than the Nikon one.

Canon Lens Production 1 - YouTube

Canon Lens Production 2 - YouTube

Canon Lens Production 3 - YouTube