To prove to skeptical New York World’s Fair visitors that no trickery was involved in creating television images, a special order was made to RCA’s engineering wing to build a transparent version of Vassos’ TRK-12 cabinet. The cabinet was constructed from DuPont’s new Lucite plastic, giving viewers a clear picture of the set’s inner workings.

Today in 1939, the 1939 New York World’s Fair, “Building the World of Tomorrow,” had its grand opening, with 206,000 people in attendance. The April 30 date coincided with the 150th anniversary of George Washington’s inauguration as President in New York City. President Franklin D. Roosevelt gave the opening day address and his speech was broadcast not only over the various radio networks but also televised in what would be the first of only two appearances he made on television. RCA-owned NBC used the event to inaugurate regularly scheduled television broadcasts in New York City. The service aired two hours of programs a week in order to “to make the art of television available to the public.” By the end of the year, a thousand receivers were sold in the U.S. The RCA receivers cost several hundred dollars and their screens were only about five inches across.