Leaning Tower of Pisa

Leaning Tower of Pisa

Overview
The Leaning Tower of Pisa or simply the Tower of Pisa (Torre di Pisa) is the campanile
Campanile
Campanile is an Italian word meaning "bell tower" . The term applies to bell towers which are either part of a larger building or free-standing, although in American English, the latter meaning has become prevalent.The most famous campanile is probably the Leaning Tower of Pisa...

, or freestanding bell tower, of the cathedral
Cathedral
A cathedral is a Christian church that contains the seat of a bishop...

 of the Italian city of Pisa
Pisa
Pisa is a city in Tuscany, Central Italy, on the right bank of the mouth of the River Arno on the Tyrrhenian Sea. It is the capital city of the Province of Pisa...

. It is situated behind the Cathedral and is the third oldest structure in Pisa's Cathedral Square (Piazza del Duomo) after the Cathedral and the Baptistry.

The height of the tower is 55.86 m (183.27 ft) from the ground on the low side and 56.70 m (186.02 ft) on the high side.
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Encyclopedia
The Leaning Tower of Pisa or simply the Tower of Pisa (Torre di Pisa) is the campanile
Campanile
Campanile is an Italian word meaning "bell tower" . The term applies to bell towers which are either part of a larger building or free-standing, although in American English, the latter meaning has become prevalent.The most famous campanile is probably the Leaning Tower of Pisa...

, or freestanding bell tower, of the cathedral
Cathedral
A cathedral is a Christian church that contains the seat of a bishop...

 of the Italian city of Pisa
Pisa
Pisa is a city in Tuscany, Central Italy, on the right bank of the mouth of the River Arno on the Tyrrhenian Sea. It is the capital city of the Province of Pisa...

. It is situated behind the Cathedral and is the third oldest structure in Pisa's Cathedral Square (Piazza del Duomo) after the Cathedral and the Baptistry.

The height of the tower is 55.86 m (183.27 ft) from the ground on the low side and 56.70 m (186.02 ft) on the high 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 14500 metric ton. The tower has 296 or 294 steps; the seventh floor has two fewer steps on the north-facing staircase. Prior to restoration work performed between 1990 and 2001, the tower leaned at an angle of 5.5 degrees, but the tower now leans at about 3.99 degrees. This means that the top of the tower is displaced horizontally 3.9 metre from where it would be if the structure were perfectly vertical.

A popular tourist activity is to pose for photographs pretending to "hold up" the leaning tower and preventing it from falling. The illusion is created through the principle of forced perspective
Forced perspective
Forced perspective is a technique that employs optical illusion to make an object appear farther away, closer, larger or smaller than it actually is. It is used primarily in photography, filmmaking and architecture...

.

Construction


Construction of the tower occurred in three stages across 177 years. Work on the ground floor of the white marble campanile began on August 8, 1173, during a period of military success and prosperity. This ground floor is a blind arcade
Blind arcade
A blind arcade is an arcade that is composed of a series of arches that has no actual openings and that is applied to the surface of a wall as a decorative element: i.e. the arches are not windows or openings but are part of the masonry face. It is designed as an ornamental architectural element,...

 articulated by engaged columns with classical Corinthian capitals
Capital (architecture)
In architecture the capital forms the topmost member of a column . It mediates between the column and the load thrusting down upon it, broadening the area of the column's supporting surface...

.

The tower began to sink after construction had progressed to the second floor in 1178. This was due to a mere three-metre foundation, set in weak, unstable subsoil
Subsoil
Subsoil, or substrata, is the layer of soil under the topsoil on the surface of the ground. The subsoil may include substances such as clay and/or sand that has only been partially broken down by air, sunlight, water, wind etc., to produce true soil...

, a design that was flawed from the beginning. Construction was subsequently halted for almost a century, because the Republic of Pisa
Republic of Pisa
The Republic of Pisa was a de facto independent state centered on the Tuscan city of Pisa during the late tenth and eleventh centuries. It rose to become an economic powerhouse, a commercial center whose merchants dominated Mediterranean and Italian trade for a century before being surpassed and...

 was almost continually engaged in battles with Genoa
Republic of Genoa
The Most Serene Republic of Genoa |Ligurian]]: Repúbrica de Zêna) was an independent state from 1005 to 1797 in Liguria on the northwestern Italian coast, as well as Corsica from 1347 to 1768, and numerous other territories throughout the Mediterranean....

, Lucca
Republic of Lucca
The Republic of Lucca was an ancient State of Tuscany which lasted from 1160 to 1805.After the death of Matilda of Tuscany, the city of Lucca began to constitute itself an independent commune, with a charter in 1160. For almost 500 years, Lucca remained an independent republic...

 and Florence
Florence
Florence is the capital city of the Italian region of Tuscany and of the province of Florence. It is the most populous city in Tuscany, with approximately 370,000 inhabitants, expanding to over 1.5 million in the metropolitan area....

. This allowed time for the underlying soil to settle. Otherwise, the tower would almost certainly have toppled. In 1198 clocks were temporarily installed on the third floor of the unfinished construction.

In 1272 construction resumed under Giovanni di Simone, architect of the Camposanto. In an effort to compensate for the tilt, the engineers built upper floors with one side taller than the other. Because of this, the tower is actually curved. Construction was halted again in 1284, when the Pisans were defeated by the Genoans in the Battle of Meloria
Battle of Meloria (1284)
The Battle of Meloria was fought between 5 and 6 August 1284 near the Meloria islet, in the Tyrrhenian Sea between the Genoese and the Pisan fleet, as part of the Genoese-Pisan War...

.

The seventh floor was completed in 1319. It was built by Tommaso di Andrea Pisano, who succeeded in harmonizing the Gothic
Gothic architecture
Gothic architecture is a style of architecture that flourished during the high and late medieval period. It evolved from Romanesque architecture and was succeeded by Renaissance architecture....

 elements of the bell-chamber with the Romanesque
Romanesque architecture
Romanesque architecture is an architectural style of Medieval Europe characterised by semi-circular arches. There is no consensus for the beginning date of the Romanesque architecture, with proposals ranging from the 6th to the 10th century. It developed in the 12th century into the Gothic style,...

 style of the tower. There are seven bells, one for each note of the musical major scale. The largest one was installed in 1655. The bell-chamber was finally added in 1372.

After a phase (1990–2001) of structural strengthening, the tower is currently undergoing gradual surface restoration, in order to repair visual damage, mostly corrosion and blackening. These are particularly pronounced due to the tower's age and its exposure to wind and rain.

Timeline

  • On January 5, 1172, Donna Berta di Bernardo, a widow and resident of the house of dell'Opera di Santa Maria, bequeathed sixty soldi
    Solidus (coin)
    The solidus was originally a gold coin issued by the Romans, and a weight measure for gold more generally, corresponding to 4.5 grams.-Roman and Byzantine coinage:...

     to the Opera Campanilis petrarum Sancte Marie. The sum was then used toward the purchase of a few stones which still form the base of the bell tower.
  • On August 9, 1173, the foundations of the Tower were laid.
  • Nearly four centuries later Giorgio Vasari
    Giorgio Vasari
    Giorgio Vasari was an Italian painter, writer, historian, and architect, who is famous today for his biographies of Italian artists, considered the ideological foundation of art-historical writing.-Biography:...

     wrote : "Guglielmo, according to what is being said, in [this] year 1174 with Bonanno as sculptor, laid the foundations of the belltower of the cathedral in Pisa."

  • Another possible builder is Gerardo di Gerardo. His name appears as a witness to the above legacy of Berta di Bernardo as "Master Gerardo", and as a worker whose name was Gerardo.
  • A more probable builder is Diotisalvi
    Diotisalvi
    Diotisalvi, Deotisalvi or Deustesalvet was an architect from Pisa, Italy, active in the 12th century in Pisa. Little is known of him.- Biography :...

    , because of the construction period and the structure's affinities with other buildings in Pisa. But he usually signed his works, and there is no signature by him in the belltower.
  • Giovanni di Simone was heavily involved in the completion of the tower, under the direction of Giovanni Pisano
    Giovanni Pisano
    Giovanni Pisano was an Italian sculptor, painter and architect. Son of the famous sculptor Nicola Pisano, he received his training in the workshop of his father....

    , who at the time was master builder of the Opera di Santa Maria Maggiore. He could be the same Giovanni Pisano who completed the belfry tower.
  • Giorgio Vasari indicates that Tommaso di Andrea Pisano was the designer of the belfry between 1360 and 1370.
  • On December 27, 1233, the worker Benenato, son of Gerardo Bottici, oversaw the continuation of the construction of the belltower.
  • On February 23, 1260, Guido Speziale, son of Giovanni, a worker on the cathedral Santa Maria Maggiore, was elected to oversee the building of the Tower.
  • On April 12, 1264, the master builder Giovanni di Simone and 23 workers went to the mountains close to Pisa to cut marble. The cut stones were given to Rainaldo Speziale, worker of St. Francesco.

Architect


There has been controversy
Controversy
Controversy is a state of prolonged public dispute or debate, usually concerning a matter of opinion. The word was coined from the Latin controversia, as a composite of controversus – "turned in an opposite direction," from contra – "against" – and vertere – to turn, or versus , hence, "to turn...

 about the real identity of the architect of the Leaning Tower of Pisa. For many years, the design was attributed to Guglielmo and Bonanno Pisano
Bonanno Pisano
Bonanno Pisano , active in the 1170s and 1180s, was an Italian sculptor, mixing Byzantine and classical elements. Giorgio Vasari wrongly attributed the realisation of the Leaning Tower of Pisa to him in his Vite. Pisano was born in Pisa and worked there most of his life...

, a well-known 12th-century resident artist of Pisa, famous for his bronze
Bronze
Bronze is a metal alloy consisting primarily of copper, usually with tin as the main additive. It is hard and brittle, and it was particularly significant in antiquity, so much so that the Bronze Age was named after the metal...

 casting, particularly in the Pisa Duomo. Bonanno Pisano left Pisa in 1185 for Monreale
Monreale
Monreale is a town and comune in the province of Palermo, in Sicily, Italy, on the slope of Monte Caputo, overlooking the very fertile valley called "La Conca d'oro" , famed for its orange, olive and almond trees, the produce of which is exported in large quantities...

, Sicily, only to come back and die in his home town. A piece of cast with his name was discovered at the foot of the tower in 1820, but this may be related to the bronze door in the façade of the cathedral that was destroyed in 1595. However recent studies seem to indicate Diotisalvi
Diotisalvi
Diotisalvi, Deotisalvi or Deustesalvet was an architect from Pisa, Italy, active in the 12th century in Pisa. Little is known of him.- Biography :...

 as the original architect due to the time of construction and affinity with other Diotisalvi works, notably the bell tower of San Nicola and the Baptistery
Baptistery
In Christian architecture the baptistry or baptistery is the separate centrally-planned structure surrounding the baptismal font. The baptistry may be incorporated within the body of a church or cathedral and be provided with an altar as a chapel...

, both in Pisa. However, he usually signed his works and there is no signature by him in the bell tower which leads to further speculation.

History following construction


Galileo Galilei
Galileo Galilei
Galileo Galilei , was an Italian physicist, mathematician, astronomer, and philosopher who played a major role in the Scientific Revolution. His achievements include improvements to the telescope and consequent astronomical observations and support for Copernicanism...

 is said to have dropped two cannon balls
Galileo's Leaning Tower of Pisa experiment
right|thumb|Hammer and Feather Drop - [[Apollo 15]] [[astronaut]] [[David Scott]] on the Moon recreating Galileo's famous experiment....

 of different mass
Mass
Mass can be defined as a quantitive measure of the resistance an object has to change in its velocity.In physics, mass commonly refers to any of the following three properties of matter, which have been shown experimentally to be equivalent:...

es from the tower to demonstrate that their speed
Speed
In kinematics, the speed of an object is the magnitude of its velocity ; it is thus a scalar quantity. The average speed of an object in an interval of time is the distance traveled by the object divided by the duration of the interval; the instantaneous speed is the limit of the average speed as...

 of descent was independent of their mass. However, this is considered an apocryphal tale, its only source being Galileo's secretary.

During World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

, the Allies
Allies of World War II
The Allies of World War II were the countries that opposed the Axis powers during the Second World War . Former Axis states contributing to the Allied victory are not considered Allied states...

 discovered that the Germans
Germans
The Germans are a Germanic ethnic group native to Central Europe. The English term Germans has referred to the German-speaking population of the Holy Roman Empire since the Late Middle Ages....

 were using the tower as an observation post. A U.S. Army sergeant
Sergeant
Sergeant is a rank used in some form by most militaries, police forces, and other uniformed organizations around the world. Its origins are the Latin serviens, "one who serves", through the French term Sergent....

 was briefly entrusted with the fate of the tower and his decision not to call in an artillery
Artillery
Originally applied to any group of infantry primarily armed with projectile weapons, artillery has over time become limited in meaning to refer only to those engines of war that operate by projection of munitions far beyond the range of effect of personal weapons...

 strike kept the tower from being destroyed.
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 vital role that this element played in promoting the tourism industry of Pisa.

A multinational task force
Task force
A task force is a unit or formation established to work on a single defined task or activity. Originally introduced by the United States Navy, the term has now caught on for general usage and is a standard part of NATO terminology...

 of engineers
Engineering
Engineering is the discipline, art, skill and profession of acquiring and applying scientific, mathematical, economic, social, and practical knowledge, in order to design and build structures, machines, devices, systems, materials and processes that safely realize improvements to the lives of...

, mathematician
Mathematician
A mathematician is a person whose primary area of study is the field of mathematics. Mathematicians are concerned with quantity, structure, space, and change....

s and historians gathered on the Azores
Azores
The Archipelago of the Azores is composed of nine volcanic islands situated in the middle of the North Atlantic Ocean, and is located about west from Lisbon and about east from the east coast of North America. The islands, and their economic exclusion zone, form the Autonomous Region of the...

 islands to discuss stabilisation methods. It was found that the tilt was increasing in combination with the softer foundations on the lower side. Many methods were proposed to stabilise 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
World Heritage Site
A UNESCO World Heritage Site is a place that is listed by the UNESCO as of special cultural or physical significance...

 along with the neighbouring cathedral
Cathedral
A cathedral is a Christian church that contains the seat of a bishop...

, baptistery
Baptistery
In Christian architecture the baptistry or baptistery is the separate centrally-planned structure surrounding the baptismal font. The baptistry may be incorporated within the body of a church or cathedral and be provided with an altar as a chapel...

 and cemetery.

On January 7, 1990, after over two decades of stabilisation studies, 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 ton 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.

Alternative candidates


Two German churches have challenged the tower's status as the world's most lop-sided building: the 15th-century square Leaning Tower of Suurhusen
Leaning Tower of Suurhusen
The Leaning Tower of Suurhusen is a late medieval steeple in Suurhusen, a village in the East Frisian region of northwestern Germany. According to the Guinness World Records it was the most tilted tower in the world, though in 2010 the newly erected Capital Gate tower in Abu Dhabi claimed this...

 and the 14th century bell tower in the town of Bad Frankenhausen. Guinness World Records
Guinness World Records
Guinness World Records, known until 2000 as The Guinness Book of Records , is a reference book published annually, containing a collection of world records, both human achievements and the extremes of the natural world...

 measured the Pisa and Suurhusen towers, finding the former's tilt to be 3.97 degrees. In June 2010 Guinness World Records certified the Capital Gate
Capital Gate
Capital Gate is a mixed use skyscraper in Abu Dhabi adjacent to the Abu Dhabi National Exhibition Centre designed with a striking lean. At and 35 stories, it is one of the tallest buildings in the city and features a dramatic 18-degree incline to the west. The owner and developer of Capital Gate...

 building in Abu Dhabi
Abu Dhabi
Abu Dhabi , literally Father of Gazelle, is the capital and the second largest city of the United Arab Emirates in terms of population and the largest of the seven member emirates of the United Arab Emirates. Abu Dhabi lies on a T-shaped island jutting into the Persian Gulf from the central western...

, UAE as the "World's Furthest Leaning Man-made Tower". The Capital Gate
Capital Gate
Capital Gate is a mixed use skyscraper in Abu Dhabi adjacent to the Abu Dhabi National Exhibition Centre designed with a striking lean. At and 35 stories, it is one of the tallest buildings in the city and features a dramatic 18-degree incline to the west. The owner and developer of Capital Gate...

 tower has an 18-degree slope, almost five times more than the Pisa Tower; however the Capital Gate tower has been deliberately engineered to slant. The Leaning Tower of Wanaka in New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...

, also deliberately built, leans at 53 degrees to the ground.

Technical information


  • Elevation of Piazza del Duomo: about 2 metres (6 feet, DMS)
  • Height from the ground floor: 55.863 metres (183 ft 3 in), 8 stories
  • Height from the foundation floor: 58.36 metres (191 ft 47 in)
  • Outer diameter of base: 15.484 metre
  • Inner diameter of base: 7.368 metre
  • Angle of slant: 3.97 degrees or 3.9 metre from the vertical
  • Weight: 14700 metric ton
  • Thickness of walls at the base: 2.4 metre
  • Total number of bells: 7, tuned to musical scale
    Musical scale
    In music, a scale is a sequence of musical notes in ascending and descending order. Most commonly, especially in the context of the common practice period, the notes of a scale will belong to a single key, thus providing material for or being used to conveniently represent part or all of a musical...

    , 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 1719–1721 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 or La Giustizia, cast in 1262 by Lotteringo, weight 1,014 kg (2,235 lb)
    • 6th bell: Il Vespruccio (2nd small one), cast in the 14th century and again in 1501 by Nicola di Jacopo, weight 1,000 kg (2,205 lb)
    • 7th bell: Dal Pozzo
      Carlo Antonio Dal Pozzo
      Carlo Antonio Dal Pozzo was an Italian prelate, who was archbishop metropolita of the Pisa Diocese.He came from the noble family of Dal Pozzo Della Cisterna of Biella...

      , cast in 1606 and again in 2004, weight 652 kg (1,437 lb)
  • Number of steps to the top: 296


About the 5th bell: The name Pasquareccia comes from Easter, because it used to ring on Easter day. However, this bell is older than the bell-chamber itself, and comes from the tower Vergata in Palazzo Pretorio in Pisa, where it was called La Giustizia (The Justice). The bell was tolled to announce executions of criminals and traitors, including Count Ugolino
Ugolino della Gherardesca
Count Ugolino della Gherardesca , count of Donoratico, was an Italian nobleman, politician and naval commander. He was frequently accused of treason and features prominently in Dante's Divine Comedy.-Biography:...

 in 1289.
A new bell was installed in the belltower at the end of the 18th century to replace the broken Pasquareccia.

See also

  • List of leaning towers
  • Round tower
    Round tower
    Round tower may refer to:Types of tower:* Irish round tower, a type of early mediaeval stone tower* Broch, a type of Iron Age drystone structure found in Scotland* Round-tower church, a type of church found mainly in England...

    , for other types of round towers
  • Leaning Tower of Niles
    Leaning Tower of Niles
    The Leaning Tower of Niles, Illinois, was completed in 1934 by industrialist Robert Ilg as part of a recreation park for employees of the Ilg Hot Air Electric Ventilating Company of Chicago. It is situated at 6300 W...

    , a replica of the Tower of Pisa
  • Torre delle Milizie
    Torre delle Milizie
    The Torre delle Milizie is a tower in Rome, Italy, annexed to the Trajan's Market in the Imperial fora.One of the main medieval monuments of the city, the tower is on a square plan, its base sides measure 10.5 x 9.5 m, and it currently stands at almost 50 meters...

    , a tilting medieval tower in Rome
  • Machang
    Machang
    Machang is a territory of Kelantan, Malaysia. It is bordered by the districts of Kota Bharu to the north, Pasir Puteh to the east, Tanah Merah to the west and Kuala Krai to the south. It is home to one of the branch campuses of Universiti Teknologi MARA...

     – another leaning tower
  • The Leaning Temple of Huma
    The Leaning Temple of Huma
    The Leaning Temple of Huma is the only leaning temple in the world and the only one of its kind in India. It is located in Huma, a village situated on the left bank of the Mahanadi, 23 km south of Sambalpur in the Indian state of Orissa. The temple is dedicated to the Hindu god Shiva.Nobody...

     – Only leaning temple in the World
  • The Greyfriars Tower – the remains of a Franciscan monastery in King's Lynn
    King's Lynn
    King's Lynn is a sea port and market town in the ceremonial county of Norfolk in the East of England. It is situated north of London and west of Norwich. The population of the town is 42,800....

    . It is also leaning and is consequently nicknamed 'The Leaning Tower of Lynn' in reference to the Leaning Tower of Pisa.

External links



  • Official website
  • Piazza dei Miracoli digital media archive (creative commons
    Creative Commons
    Creative Commons is a non-profit organization headquartered in Mountain View, California, United States devoted to expanding the range of creative works available for others to build upon legally and to share. The organization has released several copyright-licenses known as Creative Commons...

    -licensed photos, laser scans, panoramas), data from a University of Ferrara
    University of Ferrara
    The University of Ferrara is the main university of the city of Ferrara in the Emilia-Romagna region of northern Italy. In the years prior to the First World War the University of Ferrara, with more than 500 students, was the best attended of the free universities in Italy...

    /CyArk
    CyArk
    CyArk is a 501 nonprofit organization located in Oakland, California, United States. The company's website refers to it as a "digital archive of the world’s heritage sites for preservation and education"...

    research partnership, includes 3D scan data from Leaning Tower.