From the 2007 US Federal Reserve meeting transcripts, Meeting of the Federal Open Market Committee (FOMC) on September 18, 2007, economist Karen Johnson during a discussion of the Northern Rock debacle —

MS. JOHNSON. But, I have to say—as when President Fisher asked that question about
whether we know what we don’t know, to which, of course, the answer is always “no”—
[laughter] five days ago, I wouldn’t have brought up Northern Rock. So, I can’t promise you
that there aren’t—
MR. FISHER. Previously Newcastle, should have been called Sandcastle. [Laughter]
MS. JOHNSON. The Spanish banks, for example, and the Spanish mortgage market are places, if I were going to dig deeper and look for hidden problems, that are a possibility.

That’s a viewpoint that had trouble gaining traction among senior Spanish officials for another 3 years.