why does the leaning tower of pizza lean

In 1990 it closed its doors to the public as a security measure and after several works of restructuring, on June 16th 2001 opened its doors again. In 1987, UNESCO declared Patrimony of the Humanity to the whole patrimonial group of the Cathedral Square. In 1964 the Italian government asked for help to prevent the Tower of Pisa from collapsing. The Tower of Pisa measures 55.86 meters of height with an estimated weight of 14,700 tons and an inclination of about 4 ° extending 3.9 m of the vertical. This famous tower began to tilt when its construction began in 1173. The Tower of Pisa in Italian “Torre Pendente di Pisa” is located in the city of Pisa, exactly in the Piazza del Duomo of Pisa known as “Piazza dei Miracoli” (Cathedral Square). What is the Leaning Tower of Pisa nowadays? Until 1990, the tilt of the tower continued to increase from 1 to 1.2 mm. The result was tremendous, this provoked a new tilt and in 1918 the Plumbing deviation reached 5.1 m. The architect Alessandro Gherardesca made the first restoration in 1835 eliminating the muddy soil and replacing it with a marble base. The inclination of the tower slowed down during the following centuries, it is believed that its weight was an important factor allowing a certain stabilization of the building. According to Vasari, Nicola Pisano and his son Giovanni deserve credit for this work.

Tommaso Pisano continued the construction of the bell tower whose works concluded in 1372.

In 1298 a plummet deviation of 1.43 m was measured and 60 years later this figure had increased to 1.63 m. Giovanni di Simone, 100 years later, resumed work trying to compensate for the inclination of the tower by vertically building four floors, however the results were not as expected, the bell tower was still leaning and the works stopped again.

This period was very important and allowed the settlement of the ground, otherwise the tower would have collapsed.

to the southeast, due to the unstable subsoil on which the tower was built, thus ceasing its construction. With the construction of the third floor in 1178, the tower bent 5 cm. The architect Bonanno Pisano began its construction in 1173 with the first floor which was surrounded by 15 columns in white marble with classic capitals and blind arches. It took 3 stages and 177 years to build the Tower of Pisa. A little of history of the Leaning Tower of Pisa

Why does the leaning tower of pizza lean