Many slopes of Hong Kong have been “reformed” such as on this picture. Concrete is poured around trees and drainage holes are made to secure the slope. Each of these simili-natural concrete walls even have an identification number (I kid you not), perhaps for use by maintenance teams.
This is the first time that I take a closer look at these walls, and we notice that there are blocks protruding out of them. Someone wants to venture a theory on this one?