Discovered tablets discussed on ancient aliens show.

On one of the episodes they talked about tablets or something that were facing backwards in a temple that actually mentioned the 12-21-12 date. They said it was one of the only ones to mention the date and that it mentioned the return of their gods on that date. Does anyone know where I can find info about that? I couldnt find anything on google. Just didnt know how to word it I guess. Thanks.