There were four rolls of film in my dad's old box of pictures that had never been developed. I took three of them in to London Drugs (the fourth will have to go to specialist photo lab since it's not standard C-41 process film). One came out completely blank. Two had pictures on them. This is the second one I scanned. The images are from a swim-meet at at Fidalgo Pool, Anacortes, Washington. Spring (May or June) 1976. This film sat undeveloped for 37½ years. It's pretty amazing that it came out all!
Source: http://www.mbarrick.net/blog/131130/anacortes-wa-1976