Just looked at that KLM picture again. When was that large area of what looks like grass in the apron removed- is it an optical illusion?
This photo was posted by Buster the Bear sometime ago. If someone can date this photo then here is the answer. A close examination of the photo will show the new curved concrete that replaced the curved grass in front of the hangar, which is marked off with workman's oil lamps. Also what looks like the contraption that men would sit on while smoothing the concrete can be seen in front of the barrel.
