The campanile of Pisa Cathedral is known worldwide as the Leaning Tower of Pisa. Situated to the rear of the Cathedral it is 55.86m tall on the low side and 56.67m on its high side. The tower is circular in shape and has eight floors. There are seven bells on the eighth floor each representing a musical note on the major scale. The Leaning Tower of Pisa was declared a Unesco World Heritage Site in 1987 and is a major tourist attraction.
Construction of the Leaning Tower of Pisa began in 1173. The Tower began to tilt during construction of the first three stories. This was due to inadequate foundations on ground which was too soft on one side. Construction was halted on several occasions due to wars and also to allow for solutions to be found to correct the lean. One solution was to make the top five stories slightly taller on the short side in an effort to compensate for the lean. However the tilt continued to increase.
It took over 200 years to complete the construction of the Leaning Tower of Pisa during which time the tower had many additions and modifications. All the modifications failed to stop the tower’s continually increasing tilt. Following a request for help from the Italian Government a meeting of experts was held on the Azores in 1964 to find ways to prevent the tower from falling.
Over 800 years after the foundations were laid the tower was closed to the public for safety reasons. Works were carried out to slightly straighten the tower and prevent its collapse. The modifications took over ten years to complete and the tower was again opened to the public on December 15th 2001. In 2008 it was announced that the Tower had stopped moving for the first time in its history.
The Leaning Tower of Pisa was closed to the public for the first time in history in the year 1990 On This Day.
Leaning Tower of Pisa
Photo by Salim Virji 
Leaning Tower of Pisa with Duomo