Here is one of my favorite 1964-65 New York Worlds Fair Collectibles. A boxed set of 28 picture cards or Flash Cards as they are known. These cards are not numbered and depending on which box you bought, there were always a few different pictures in each box. Below are a sample of some of the cards.
These cards pictured major exhibits and attractions at the fair, either as artist renditions or models. And as the back of the box read: "For Mailing / Affix Addressed Label and Stamp Over Pictured Area". ENJOY!