This article starts with an old wive's tale as its first sentence. I'm not criticising the rest of the article, but that is a lie that has been debunked over and over.
You even need binoculars and then only from low earth orbit, where you can easily see cities and dams with the naked eye. No man made structures are visible from the moon by the way.
The Great Wall is narrower than my apartment block. Still a marvel and wonder of the world though.
We must not make statements on commonly held beliefs after just hearing it from someone else. Be critical. Do your research. Question everything, especially such old stories. There is no excuse not to in this day and age.
I agree that you should always do your own research. I usually do. Unfortunately there are some things which I believe since I was a kid, and I did not know how to do it or if I should do it back then. Some of those things I question, some of those I forget to. Thank you for reminding me of that!
Humble reply... I am impressed.