Yes, it says under! Now, I'll tell you why I prefer it. First of all I think "over the rainbow" is way overrated. Do you know anyone who has ever been there? Me, neither. Second, although I'm not afraid of regular heights (like, oh say, 5'2") I think "over the rainbow" would give me a lifelong phobia. I mean have you seen how high it really is? Me, too. Third--who knows how to get up there? With a ladder? Yeah, right, that's what I thought. Or maybe a plane could get you there. No? Fine by me. Maybe a wish? No, no we'd need a star for that and I'm fresh out.

 I know--we need a know-it-all! That's it; and I happen to know (very funny) where several of those are. You find one of those and they could not only get you there, play tour guide along the way. Maybe even go by way of the moon, sort-a like a two-fer. So now you know why I prefer "under the rainbow". 
Now if I could just find a shade tree and a chair, wait... my know-it-all just walked in. Okay, now I've got mine, you'll have to find your own, or maybe I'll just let you come along for the ride up!