Leaning Tower of Pisa

Photo Credit: Jessie Benaglio

The Leaning Tower of Pisa in Pisa, Italy is the campanile, or freestanding bell tower, of the cathedral. The tower now leans at about 3.99 degrees. The top of the tower is displaced horizontally 12 ft 10 in from where it would be if the structure were perfectly vertical. Before restoration between 1990 and 2001, the tower leaned 5.5 degrees. The work involved to stabilize the tower was to extract 70 tons of earth from the northern side to encourage the tower to right itself which corrected the tower in a more upright position. The foundations only extend 3 meters below the surface. This was not deep enough to get past the soft soil. Hi-tech monitors are embedded in soil beneath its foundations and in the tower itself now show that it has stopped moving completely.