...is the twenty-fourth letter of the Greek alphabet, you might have thought that it would be disallowable under Scrabble rules as a 'foreign word' ['foreign letter'???], wouldn't you?
Not so, apparently: at least, not according to the nifty online word checker: click here
(Sorry - a quick OCD O.D.!)
Great piece and great photo, by the way!
Cheers,
pplater.