I have the impression that the artist makes a tour of these cities and on every road, if we were there, we could find one of these sculptures. He may also be portraying important events that occurred and in the places where they occurred.

You summed it up well and I agree with you on that.

As about ways of learning, this type of illustrating things would help me a lot as I have visual memory and remember what I see. So obviously this would help me a lot.