Leaning Tower of Pisa
The
Leaning Tower of Pisa (
Italian:
Torre pendente di Pisa or simply
La Torre di Pisa) is the
campanile, or bell tower, of the cathedral of the
Italian city of
Pisa. It is situated behind the Cathedral and it is the third structure in Pisa's
Campo dei Miracoli (
field of Miracles).
The tower is famous for its noticeable lean. It was intended to stand vertically so as to serve as a bell tower, but began leaning soon after construction started in 1173 due to a poorly laid foundation.
The height of the tower is 55.86 m (183.27
ft) from the ground on the lowest side and 56.70 m (186.02 ft) on the highest side. The width of the walls at the base is 4.09 m (13.42 ft) and at the top 2.48 m (8.14 ft). Its weight is estimated at 14,500
tonnes. The tower has 294 steps.
The construction of the Tower of Pisa was performed in three stages over a period of about 200 years. Construction of the first floor of the white marble
campanile began on
August 9,
1173, a period of military success and prosperity. This first floor is surrounded by pillars with classical capitals, leaning against blind arches. Today it is still unscarred from the weather and age.
There is controversy about the identity of the architect of the Leaning Tower of Pisa. For many years the design was attributed to Guglielmo and
Bonanno Pisano, a well known twelfth century resident artist of Pisa, famous for his bronze casting, particularly in the
Pisa Duomo. Bonanno Pisano left Pisa in 1185 to
Monreale, Sicily, only to come back and die in his home town. His
sarcophagus at the foot of the tower was discovered in 1820.
After the third floor was built in
1178, the tower acquired a lean, due to a mere three-meter foundation in weak, unstable subsoil. The design of this tower was flawed from the beginning. Construction was halted for almost 100 years because the Pisans were almost continually engaged in battles with
Genoa,
Lucca and
Florence. This allowed for the underlying soil to settle, otherwise the tower would almost certainly have toppled. In 1198 some clocks were temporarily installed on the unfinished construction.
In
1272 construction was resumed by the Giovanni di Simone, architect of the
Camposanto. Another four floors were built at an angle to compensate for the tilt. Construction again stopped in 1284, when the Pisans were defeated by the Genoans in the
battle of Meloria.
Only in
1372 was the last floor, the bell-chamber, built by
Tommasso di Andrea Pisano and bells installed. He succeeded in harmonizing the
Gothic elements of the bell-chamber with the
Romanesque style of the tower. There are seven bells, one for each note of the musical scale. The largest one was installed in 1655.
Galileo Galilei is said to have dropped two
cannon balls of different masses from this tower to demonstrate that their descending speed was independent of their mass. This story, though reported by Galileo's own student, is widely considered to be a myth.
In 1838 the architect Alessandro Della Gherardesca excavated a walkway around the tower to make the base of the tower visible again. This caused a flooding of the base and again an increase in the inclination.
Benito Mussolini ordered the tower be returned to a vertical position, so
concrete was poured into its
foundation. The results were unexpected and sank the tower further into the
soft soil.
During
World War II, the
U.S. army destroyed nearly all towers in Pisa due to the potential threat from
snipers. The Leaning Tower was scheduled to be blown up as well; a last-minute order to retreat prevented the destruction.
On
February 27,
1964, the government of
Italy requested aid in preventing the tower from toppling. A multinational task force of engineers, mathematicians and historians was assigned and met on the
Azores islands to discuss stabilization methods. After over two decades of work on the subject, the tower was closed to the public in January 1990. In the time that the tower was closed 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 concerns. After a decade of corrective reconstruction and stabilization efforts the tower was reopened to the public on
December 15,
2001. Many methods were proposed to stabilize the tower including the addition of 800 metric tons of lead counterweights to the raised end of the base. The final solution to correcting the lean was to remove 38
m3 of soil from underneath the raised end. The tower has been declared stable for at least another 300 years.
The tower originally leaned towards the
north, but, now, after efforts to straighten it, it leans to the
south.
 |
View looking up |
*
Geographic coordinates:
*Elevation of Piazza dei Miracoli: about 2
metres (6
feet, DMS)
*Height: 55.863 metres (183 ft 3 in), 8 stories
*Outer diameter of base: 15.484 m
*Inner diameter of base: 7.368 m
*Angle of Slant: 13 degrees
*Weight: 14,700
tonnes
*Thickness of walls at the base: 8 ft (2.4 m)
*Total number of bells: 7, tuned to musical scale, clockwise
**1st bell: L'assunta, cast in 1654 by Giovanni Pietro Orlandi, weight 3,620 kg (7,981 lb)
**2nd bell: il Crocifisso, cast in 1572 by Vincenzo Possenti, weight 2,462 kg (5,428 lb)
**3rd bell: San Ranieri, cast in 1719-21 by Giovanni Andrea Moreni, weight 1,448 kg (3,192 lb)
**4th bell: La Terza (1st small one), cast in 1473, weight 300 kg (661 lb)
**5th bell: La Pasquereccia, cast in 1262 by Lotteringo, weight 1,014 kg (2,235 lb)
**6th bell: il Vespruccio (2nd small one), cast in the fourteenth century and again in 1501 by Nicola di Jacopo, weight 1,000 kg (2,205 lb)
**7th bell: Del Pozzetto, cast in 1606, weight 652 kg (1,437 lb)
*Steps to bell tower: 294
*The movie
Superman III features an evil
Superman doing several "bad deeds" around the world - one of which is straightening the Leaning Tower of Pisa, played to comedic effect. The infamous final scene of the film features Superman pushing the tower back to its normal inclination.
*
Leaning tower, for a general description of the phenomenon.
*
Round tower, for other types of round towers.
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Torre delle Milizie, a tilting medieval tower in
Rome*
Satellite view of Leaning Tower of Pisa *
Holiday Local Map Guide *
The Leaning Tower of Pisa Virtual reality movies
*
The Official Site In both English and Italian
*
How the process of inclination was stopped
