Introduced in 1976 and discontinued in 1998, the Nikon 13mm f/5.6 is often dubbed "The Holy Grail" because of its ultra-wide angle of view with minimal distortion. It was only available via special order during its production run making it one of Nikon's rarest lenses.
However, a Nikon 13mm f/5.6 lens has just appeared on eBay. If interested in bringing home this ultra-wide, ultra rare lens, a significant emptying of the wallet will be necessary.
The serial number of this particular lens translates to a production year after 1982.