Every radio aficionado can recognize at least three notes of music: G-E-C - the famous NBC chimes!
In fact there is so much history about the chimes it deserves it's own website, and someone has put a great deal of effort into creating one:
It is well worth the time to listen to each audio clip and read the history of how the chimes (aka "bells") were used and evolved over the years. But to stimulate curiosity - did you know there was a FOUR note chime signature? The site explains what special occasions it was reserved for.
What started out as this: