Recently I found a long lost go-pro style camera using metal detector, after it had fallen off an RC plane, which crashed into a tree in dense forest. Over nearly a decade the camera had been buried several centimeters into the ground, and the card inside the camera wasn't particularly well protected (just an open slot, not waterproof or anything), which made it exposed to lots of water and freezing winters for nearly a decade. After some cleaning the SD card worked perfectly, and all the data was intact. It even had the crash recorded in it. I was impressed by that. The camera didn't survive though.