This sort of reminds me of "the Sunken Sidecar of Doom", a thread on a motorcycle forum that went on for YEARS! A sidecar had been spotted mostly submerged in the muck of a tidel bore near a bridge somewhere in the Netherlands, I believe it was. I think it was spotted in a photo taken of something else and speculation on what it was and how to retrieve it went on for years. At first no one even knew where it was, but there was enough of a view of the bridge (and it was somewhat unique) that eventually it was located. The thread went on for pages and pages and pages, and eventually three or four guys went down there and retrieved the poor old rusty hulk. Mystery solved! Book closed! Fun's over.
If you wanted to read through the whole saga, googling the name should get you there.