Here, from the current revival on My Fair Lady in New York, is the "Rain in Spain" number. It is said that lyrist Alan Jay Lerner and composer Frederick Loewe would take days, weeks, even a month to perfect a song. Lerner especially took an extremely long time to do his end of the job. But inspiration hit them on this song it only took something like thirty minutes, culminating in a celebration quite like the one in the tune. It is a really spectacular stage number…