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Construction of the Tower of Pisa began in 1173. Originally intended to be a freestanding bell tower, the first stones were laid on the 9th of August, 1173.
Contents
Still standing: The lean that refused to fall
Progression of the tilt
Construction
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How engineers stabilized the tower
By the late 20th century, the Leaning Tower's tilt had reached 5.5 degrees—its top leaning 4.5 meters off center. To prevent collapse, engineers began a high-stakes stabilization effort.
Monitoring and emergency support
To begin, the tower was temporarily closed to the public in 1990 and encircled with steel cables anchored to underground concrete ring beams, acting like a seatbelt to prevent sudden movement. Engineers installed tilt sensors, laser alignment systems, and inclinometers to monitor every millimeter of motion in real time.
Counterweights
Engineers placed 600 tonnes of lead counterweights on the tower’s north side (the higher side) to slightly shift its center of gravity and slow down the tilt. This passive load helped stabilize the structure temporarily while permanent solutions were tested.
Soil extraction
The core stabilization method was underexcavation, a technique that involved removing small amounts of soil from beneath the north side of the foundation. As earth was gradually removed through angled boreholes, the ground compressed naturally, causing the heavier south side to settle and the tower to gently straighten.
Long term stability
By 2001, underexcavation had reduced the Leaning Tower’s tilt by 43.8 cm, restoring it to its early 19th-century angle of 3.97 degrees. The tower retained its iconic lean but shed the risk of collapse. Declared stable for at least 300 more years, it continues to be monitored—without any permanent addition of modern materials, preserving its historical authenticity.
The tower today: A triumph of preservation
Today, the Leaning Tower of Pisa stands not only as an architectural marvel but as a testament to the success of modern preservation. Its lean—now stabilized at 3.97 degrees—is no longer a structural threat, but a defining feature that continues to captivate millions each year.
Visitors can climb its 273 spiral steps for sweeping views of the Piazza dei Miracoli and the Tuscan skyline, or simply admire the tower’s unmistakable tilt from below, one of the most photographed sights in all of Italy.
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Frequently asked questions about Leaning Tower of Pisa's fall
Has the tower ever fallen?
No, the Leaning Tower of Pisa has never fallen. Despite its dramatic tilt, careful engineering and stabilization efforts have kept it standing for over 850 years.
Will it ever fall down?
No, the Leaning Tower of Pisa is not in danger of collapsing for at least another 300 years since efforts have been made to stabilize the monument.
At what angle will the tower fall?
According to computer algorithms, the Leaning Tower of Pisa should have fallen when it tilted to an angle of 5.44 degrees, but it continued to stand even when it leaned at 5.5 degrees. Engineers quickly got to work to stabilize the tower before it collapsed.
How many years has the tower been slowly falling?
The Leaning Tower of Pisa began tilting just a few years after construction started in 1173, due to unstable ground beneath its foundation. That means it was slowly falling for over 800 years—until engineers halted the movement with stabilization work completed in 2001.
Who led the stabilization project of the tower?
A multinational team of engineers, led by Italian professor Michele Jamiolkowski, oversaw the efforts from 1990 to 2001. Their work is now considered a landmark in geotechnical engineering.
Is it safe to visit the tower?
Yes, it is safe to visit the Leaning Tower of Pisa as engineers have stated that it's under no immediate danger of collapse.
What is the current angle of the tilt of the tower?
The current angle of tilt of the Leaning Tower of Pisa is about 4 degrees (3.97 to be accurate).
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