Re: What is causing the leaning tower of Pisa to lean?

Tamara,

The Leaning Tower of Pisa is leaning because the ground it sits on is too soft to support the weight of the tower. Usually when a building that big and heavy is put on soft ground it's built on special supports called pilings that reach all the way down to the solid rock underneath the dirt. Unfortunately, the supports used for the Tower didn't go deep enough, and the earth under the tower is slowly giving way and flowing out from under it, kind of like setting a heavy vase on top of an open tube of toothpaste.

The tower started leaning before the third floor was completed in the mid- 1200's, and it has gotten worse and worse slowly ever since. Today, one side of the tower has sunk more than six feet lower than the other side, and the top of the tower leans sixteen feet out from the base. To keep it from falling the people of Pisa have stacked piles of huge bricks on the back side of the tower to try to balance out the tilt.