Leaning Tower of Pisa begun

1173

Construction began on the free-standing bell tower of Pisa cathedral on ground so soft that the building began visibly tilting before the third story was reached. Work stopped for a century while builders debated what to do. It has been tilting and gradually leaning further ever since. Engineers would eventually compensate by building the upper stories slightly taller on one side, giving the tower a subtle banana-curve visible in close photographs.