In an episode of “The Simpsons” the set-up was Lisa is President, and Homer spends his time looking for “the gold Abraham Lincoln burried in the White House.” In the end, Lisa told Homer was just a myth.
I’ve lived in the U.S. all my life, and I’m pretty historically literate, but I’ve never heard of this myth. And there was no further explanation in the episode. The writers just assumed everyone had heard of it. What is the story of Lincoln burrying gold in the W.H.?
I don’t think there ever was any such “legend”. I think the Simpsons writers invented this – that America’s (probably) most-beloved president, famous for his honesty and frugality, would have hidden a stash of gold in the White House.
Also, I think the writers came up with this because, at a glance, it sounds like so many other legends; the hidden treasure of <famous person>, guarded over by the same’s ghost.