It is one of the most famous monuments in Italy and the world, but its history is not known to everyone. The Leaning Tower of Pisa is the bell tower of the cathedral of Santa Maria Assunta in the famous Piazza del Duomo (UNESCO World Heritage Site since 1987).
A characteristic mark of this tower is the fact that it slopes to one side in a very visible, unique and special way. The reasons for its slope date back to the time of its construction, and its safety and stability has been ensured through years of interventions, restoration and maintenance.
Precisely because of this peculiarity, it is a destination visited by hundreds of thousands of tourists every year.
It is one of the most famous monuments in Italy and the world, but its history is not known to everyone. The Leaning Tower of Pisa is the bell tower of the cathedral of Santa Maria Assunta in the famous Piazza del Duomo (UNESCO World Heritage Site since 1987).
A characteristic mark of this tower is the fact that it slopes to one side in a very visible, unique and special way. The reasons for its slope date back to the time of its construction, and its safety and stability has been ensured through years of interventions, restoration and maintenance.
Work began on 9 August 1173, and was not completed until the middle of the 14th century. The official inauguration took place in 1373. To this day it remains a destination visited by hundreds of thousands of tourists every year.
It is a free-standing bell tower 57 metres high (58.36 metres considering the foundation level). With a mass of 14,453 tonnes, it is dominated by a curved line, with round blind arcades and six storeys of loggias.
The slope of the tower is due to a series of differential failures, i.e. a series of non-uniform failures affecting the fundamental structures that become evident after the completion of the structure itself. The causes of these subsidence are to be found in the structure of the soil, which consists of soft, normal-consolidated clay. Furthermore, in ancient times, a bend of the Auser river ran through the area of the tower. The slope is in fact a characteristic feature of almost all the buildings in the square, although to a considerably lesser degree.
Over the centuries, the slope increased significantly, partly due to the suction of the water table below. In 1993, fears began to be raised for the strength of the tower, which at the time had reached a slope of as much as 4.47 metres, or approximately 4.5 degrees. Since March 2008, the tower has reached its final level of consolidation in terms of inclination, which is now 3.97 degrees again.