I thought this brief video on Youtube was interesting. It claims to be photos developed from film found in a camera that had been buried at the site of the Battle of the Bulge. The American soldier to whom the camera belonged, Louis Achambeau, was killed during that battle. Though I approach this kind of story with a bit of skepticism, it is a remarkable and historically poignant discovery.
Most of the longest surviving negatives unprocessed were recovered from Antarctic expeditions, and Everest climbs, here the film was hard frozen and as such was completly dry. To have survived in ordinary conditions in a camera body sounds very unlikely.
However I have seen 30 year old files processed with success, and only the damp is against the claim. There is not enough imformation in the report to say what happened.
On the other hand it would be easy to fake, but to what advantage, especially as the late soldiers name is connected up with the camera.