It is the recorded insert, to be played on a phonograph/record player at 33 1/2 rpm (one of two common settings), to the August 1965 issue of the National Geographic Magazine, as indicated at the center of the insert.
The National Geographic Magazine had that inserted into every copy of the August 1965 issue of NGM in commemoration of Winston Churchill's passing on 24-Jan-1965.
These are literally min- LP records, that were meant to be removed from the issue and played on an LP player so that member's could hear snippets of the funeral speeches on one side, and some audio clips of Churchill himself on the other side. To be precise: NGM termed this a "sound sheet", and originally it was bound in, but with a sort of perforation to aid in removing it.
NGM did 2 more sound sheets after this:
- "Sounds of the Space Age" in their December 1969 issue; commemorated the lunar landing that summer,
- and once more with "Songs of the Humpback Whale" in January 1979.
It was a very interesting endeavor, and for the time, quite costly, and unprecedented, and National Geographic had the resources and will to do it. As was usual.
~ Scott S.
This should give you an idea: