Q. “Dear Santa, I've been good mostly …” and the letter, with its wish list duly completed, is put into an envelope, stamped and addressed to “Santa Claus, North Pole.” Where might the letter end up? A. Without a ZIP code, the U.S. Postal Service would have difficulty completing delivery, since its sorting system begins with the ZIP code, Dan Lewis says on his Now I Know website.Read more on NewsOK.com