The Great Wall of China was finished at its northernmost location. The construction work moved up from the south-east and south-west and joined at this point. The system of building in sections was also followed on a small scale within the two great armies of workers, the eastern and western. It was carried out in the following manner: groups of about twenty workers were formed, each of which had to take on a section of the wall, about five hundred metres. A neighbouring group then built a wall of similar length to meet it. But afterwards, when the sections were fully joined, construction was not continued on any further at the end of this thousand-metre section. Instead the groups of workers were shipped off again to build the wall in completely different regions. Naturally, with this method many large gaps arose, which were filled in only gradually and slowly, many of them not until after it had already been reported that the building of the wall was complete. In fact, there are said to be gaps which have never been built in at all, although that’s merely an assertion which probably belongs among the many legends which have arisen about the structure and which, for individual people at least, are impossible to prove with their own eyes and according to their own standards, because the structure is so immense.
(Kafka, The long wall of China)