How did a century of warfare inadvertently save the tower from collapsing?

The method – known as soil extraction – saw engineers dig a series of tunnels on the north side of the tower and remove small amounts of earth. (The tower leans to the south.) Steel cables helped pull it back into its original position.

Explanation:

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workers of lowell mills were greatly benefited for the waltham type of work which was more a paternalist kind, trying to protect the integrity of this little girls coming from small farmers and providing an adequate place of work, this in an effort to avoid the issues of bad place conditions and immorality that the people in bigger industrialized cities of great britain were experimenting.

silk

indigo  

rice

all the other answers are wrong