There's a small plane sunk in the river in the Sault, and it's quite a popular dive spot here. My instructor periodically brings little things down to the plane with him to secure and leave to make it a bit more interesting for repeat dives.
Some things down there now are a concrete garden fountain, garden gnomes, a silver tea set.
There are also some wood pilings at the exit point, in about 15', and he has secured a mask and snorkel to them.
These little things keep interest alive in this dive spot. It's fun to go and see if we can find what he has added!