Re: Planet X?

"Only two actual pirates ever really buried their treasure"

Well maybe, but presumably if you were burying treasure, it would be to keep it hidden, so it's not exactly something you'd announce or record in a manner that would be likely to enter the historical record.

In a somewhat related manner, I do know that modern day marine salvagers store some of their finds in specific locations underwater, until they've gathered enough to take it into a port.

Unfortunately for the employer of an acquaintance of mine, the storage site they picked was a shipwreck that they had already cleaned out, and who's location was known. They came back months later to pick up their carefully packaged finds, only to find empty seabed. That was a seven figure loss.