It was once feared that the Tower of Pisa was on the verge of collapse, as the leaning that made it such a popular monument threatened its very existence.
But this week, in the celebration of the 850th anniversary of the monumentits guardians gave it the go-ahead and ensured that it would not disappear from tourist photos.
“Today the bell tower is a stable monument,” Andrea Maestrelli, president of the Opera della Primaziale Pisana (OPA), the millennial body that cares for the cathedral complex that includes the tower, said on Wednesday at a press conference in which They outlined the acts to celebrate their anniversary.
But it was not always like this. In the early 1990s, the tower, the centerpiece of a UNESCO World Heritage Site, reached a 4.5 degree inclination and fears for its stability led to an international effort to prevent it from collapsing, with jobs that lasted eight years since 1993.
Now, experts say that its future is “promising”, with satellite and terrestrial surveillancewhich currently tracks even the slightest change in its position, making the famous bell tower one of the most closely watched monuments in the world.
The first stone of the tower of Pisa was laid on August 9, 1173, “thanks to the donation of 60 coins made by a widow named Berta, for the construction of the bell tower of our cathedral”, declared the Archbishop of Pisa Giovanni Paolo Benotto during the press conference on Wednesday.
Tower stability problems started early. Construction was interrupted at the height of the third open level of columns due to subsidence and was not resumed until 1275, when another three levels were added.
In an attempt to straighten the tower, the top three stories were curved in the opposite direction of the lean. The tower was completed in the mid-14th century, when the bell tower was added.
At the end of the 20th century, when the slope worsened, earth was removed from under the foundation on its north side through a series of boreholes, which caused an imperceptible reduction of the slope.
The latest report from the watchdog group that oversees the monument “highlighted that the inclination has decreased by about 460 millimetersMaestrelli said, adding that the inclination has returned to that of the early 19th century. Earth was removed from under the foundation of the Leaning Tower of Pisa to help reduce its tilt. The consolidation works have allowed this tower to look to the future with “great confidence”, he added. Today the tower is the case study of one of the most complex surveillance systems in the world, explained the technical director of OPA, Roberto Cela. Thanks to an agreement between the Italian Ministry of Cultural Heritage and the OPA, experts integrate satellite monitoring with data collected at ground level. The progress of these terrestrial and satellite surveillance activities will be presented next year, within the series of events scheduled to celebrate the tower’s 850th anniversary.
