Winchester Cathedral was not built on the best of ground.  About 100 years ago, a major effort was made to save sections of the building from collapsing.  A diver spent many months under water in the pilings beneath the building bringing in material to shore everything up.  The effort was ultimately a success and some buttresses were added to take care of the rest.  However, this all was done after the walls had made some significant movement.  Today, this is still apparent when you look at some of the angles and realize that things are pointing in odd direction.  The original stone masons were not inaccurate.  Things just moved after they were done.  Their choice of foundations was more of the issue!