Missouri - Varied Industries Building at the St. Louis World's Fair (Hold-to-Light)

Hold Card to Light
Official Souvenir Postal card

Varied Industries Building
When you hold this postcard up to the light all the windows and the circles on the sidewalks light up, including the little buildings on the right.

Samuel Cupples Envelope Co.  St. Louis, Mo. Sole World's Fair Stationers.
1904