Interesting fact:

If you choose to go to Pisa on vacation, you’ll definitely want to see the famous Leaning Tower of Pisa which is a freestanding bell tower of the cathedral of the Italian city of Pisa, known worldwide for its unintended tilt. The tower's tilt began during construction, caused by an inadequate foundation on the ground which was too soft on one side to properly support the structure's weight. The tilt increased in the decades before the structure was completed and gradually increased until the structure was stabilized.