PopSci: Archive Gallery: From Chicago to Shanghai, 138 Visionary Years of World's Fairs [more inside]
The New York World’s Fair of 1939 and 1940 promised visitors they would be looking at the “World of Tomorrow”. (second link is similar to the second one here)
The Middleton Family at the New York World's Fair (1939). The Original Futurama. Featuring Elektro, the Smoking Robot.