Early this week, on a tour of the Library of Congress (LOC), I took this picture of the pre-electronic era card catalog area. I also found these statistics posted by the LOC librarians on a nearby wall.
Most of our parents know how to use card catalogs backwards and forwards so they will definitely enjoy these pictures from the good old days.
The LOC catalog is still there, though it has not been updated since 1980. Seems like yesterday.