Originally Posted by
chartreuse
Errr.... do you not think that, in the case of Greenwich, it might be the
Royal Naval Observatory?

Not according to my recollection of the sign there on the clock. It said US Naval Observatory, Washington, DC.
Check it out this weekend if you get a chance

I wont get a chance to check myself for a bit. Im in the UK at the end of the month but in Cambridge and on a tight schedule. I doubt I will have time to get there.
Wouldnt be the first time I had a faulty memory, but I remember because I was shocked when I saw it since my expectation was the same as yours.