Cecil was rigfht for the most part on that column on the Great Wall–they showed pictures of the Earth as seen from the moon in a Histroy Channel show on the Great Wall to illustrate that fact–but Vecil was (I am loathe to say) a little off on one point: The myth that you can see the Great Wall from the moon has been ingraied in human consciousness as least as far back as the 30s, when Robert Ripley put the dubious fctoid in his “Believe it or Not” comic strip. Now, I see Mr. Ripley as a sort of Cecil Adams of his time, but after watching the History Channel’s production, I have to say this time, it’s a unqualified “not.” 
First, a link to Cecil’s column. Then the
from Cecil to which you are referring.
In a previous thread , I cited references from 1909 and 1923(The National Geographic) which speculated on this.
Thanks for adding an addional source.
Robert Ripley was the Cecil Adams of his time? I must respecfully disagree. With Ripley, it’s believe it or not. With Adams, it’s believe it or else.[sup]*[/sup]
[sub]*“Or else what?” you may wonder. Or else you’re very likely to be wrong.[/sub]