The Leaning Tower of Pisa is the piazza's crowning glory.
Although only a third as high as the Washington Monument, it was a miracle of medieval engineering, probably the tallest bell towers in Europe.
With 207 columns ranged around eight stories, Tower of Pisa looks like a massive wedding cake knocked precariously askew by a clumsy giant guest.
The construction of Tower of Pisa began in 1173 and continued for about 200 years due to the onset of a series of wars. Till today, the name of the architect is a mystery. Construction of the tower occurred in three stages across 344 years. Work on the ground floor of the white marble campanile began on August 14, 1173, during a period of military success and prosperity. This ground floor is a blind arcade articulated by engaged columns with classical Corinthian capitals.
The leaning Tower of Pisa was designed as a circular bell tower that would stand 185 feet high. It is constructed of white marble. The tower has eight stories, including the chamber for the bells. The bottom story consists of 15 marble arches. Each of the next six stories contains 30 arches that surround the tower.
The final story is the bell chamber itself, which has 16 arches. There is a 297 step spiral staircase inside the tower leading to the top. The top of the leaning tower of Pisa is about 17 feet off the vertical. The tower is also slightly curved from the attempts by various architects to keep it from leaning more or falling over.
Many ideas have been suggested to straighten the Tower of Pisa, including taking it apart stone by stone and rebuilding it at a different location. In the 1920s the foundations of the tower were injected with cement grouting that has stabilized the tower to some extent.
During World War II, the Allies discovered that the Germans were using the tower as an observation post. A U.S. Army sergeant sent to confirm the presence of German troops in the tower was impressed by the beauty of the cathedral and its campanile, and thus refrained from ordering an artillery strike, sparing it from destruction.
Lead counterweights On February 27, 1964, the government of Italy requested aid in preventing the tower from toppling. It was, however, considered important to retain the current tilt, due to the role that this element played in promoting the tourism industry of Pisa.
A multinational task force of engineers, mathematicians, and historians gathered on the Azores islands to discuss stabilization methods. It was found that the tilt was increasing in combination with the softer foundations on the lower side. Many methods were proposed to stabilize the tower, including the addition of 800 tonnes of lead counterweights to the raised end of the base.
In 1987 the tower was declared as part of the Piazza del Duomo UNESCO World Heritage Site along with the neighboring cathedral, baptistery and cemetery.
On January 7, 1990, after over two decades of stabilization studies, and spurred by the abrupt collapse of the Civic Tower of Pavia in 1989, the tower was closed to the public. The bells were removed to relieve some weight, and cables were cinched around the third level and anchored several hundred meters away. Apartments and houses in the path of the tower were vacated for safety. The final solution to prevent the collapse of the tower was to slightly straighten the tower to a safer angle, by removing 38 cubic meters (50 cubic yards) of soil from underneath the raised end. The tower was straightened by 45 centimeters (18 inches), returning to its 1838 position. After a decade of corrective reconstruction and stabilization efforts, the tower was reopened to the public on December 15, 2001, and was declared stable for at least another 300 years.
In May 2008, after the removal of another 70 metric tons (77 short tons) of ground, engineers announced that the Tower had been stabilized such that it had stopped moving for the first time in its history. They stated it would be stable for at least 200 years.
With 207 columns ranged around eight stories, Tower of Pisa looks like a massive wedding cake knocked precariously askew by a clumsy giant guest.
The construction of Tower of Pisa began in 1173 and continued for about 200 years due to the onset of a series of wars. Till today, the name of the architect is a mystery. Construction of the tower occurred in three stages across 344 years. Work on the ground floor of the white marble campanile began on August 14, 1173, during a period of military success and prosperity. This ground floor is a blind arcade articulated by engaged columns with classical Corinthian capitals.
The leaning Tower of Pisa was designed as a circular bell tower that would stand 185 feet high. It is constructed of white marble. The tower has eight stories, including the chamber for the bells. The bottom story consists of 15 marble arches. Each of the next six stories contains 30 arches that surround the tower.
The final story is the bell chamber itself, which has 16 arches. There is a 297 step spiral staircase inside the tower leading to the top. The top of the leaning tower of Pisa is about 17 feet off the vertical. The tower is also slightly curved from the attempts by various architects to keep it from leaning more or falling over.
Many ideas have been suggested to straighten the Tower of Pisa, including taking it apart stone by stone and rebuilding it at a different location. In the 1920s the foundations of the tower were injected with cement grouting that has stabilized the tower to some extent.
During World War II, the Allies discovered that the Germans were using the tower as an observation post. A U.S. Army sergeant sent to confirm the presence of German troops in the tower was impressed by the beauty of the cathedral and its campanile, and thus refrained from ordering an artillery strike, sparing it from destruction.
Lead counterweights On February 27, 1964, the government of Italy requested aid in preventing the tower from toppling. It was, however, considered important to retain the current tilt, due to the role that this element played in promoting the tourism industry of Pisa.
A multinational task force of engineers, mathematicians, and historians gathered on the Azores islands to discuss stabilization methods. It was found that the tilt was increasing in combination with the softer foundations on the lower side. Many methods were proposed to stabilize the tower, including the addition of 800 tonnes of lead counterweights to the raised end of the base.
In 1987 the tower was declared as part of the Piazza del Duomo UNESCO World Heritage Site along with the neighboring cathedral, baptistery and cemetery.
On January 7, 1990, after over two decades of stabilization studies, and spurred by the abrupt collapse of the Civic Tower of Pavia in 1989, the tower was closed to the public. The bells were removed to relieve some weight, and cables were cinched around the third level and anchored several hundred meters away. Apartments and houses in the path of the tower were vacated for safety. The final solution to prevent the collapse of the tower was to slightly straighten the tower to a safer angle, by removing 38 cubic meters (50 cubic yards) of soil from underneath the raised end. The tower was straightened by 45 centimeters (18 inches), returning to its 1838 position. After a decade of corrective reconstruction and stabilization efforts, the tower was reopened to the public on December 15, 2001, and was declared stable for at least another 300 years.
In May 2008, after the removal of another 70 metric tons (77 short tons) of ground, engineers announced that the Tower had been stabilized such that it had stopped moving for the first time in its history. They stated it would be stable for at least 200 years.