Leaning Tower of Pisa:  Photo by Lee CannonCredit: Photo by Lee Cannon

The Leaning Tower of Pisa is an architectural wonder—or is it?  The architectures surely didn’t design the tower to lean at such an angle. One wonders if the tower won’t soon crash to the ground.  What makes it lean and what keeps it from falling?  Let’s start at the beginning. 

The History of the Tower of Pisa 

The Tower of Pisa is a bell tower for the cathedral in Pisa and sits behind the cathedral in Pisa’s aptly named, Campo dei Miracoli, “field of miracles.”   The history of the tower is as intriguing as the structure itself.   No one knows who the original designers are of the leaning tower, though several names are mentioned as contenders.   At first the design was credited to Guglielmo and Bonanno Pisano.  Bonanno Pisa was a 12th century local artist who was known for his bronze casting.  He left Pisa in 1185, but came back to Pisa where he eventually died.  In 1820 a piece of cast with his name was found at the foot of the tower, which many believed supported Pisano as the designer.  However, recent studies indicate Diotisalivi is the original architect due to similarities with his other designs and the time of construction of the tower.  Detractors point out Diotisalivi usually signed is work and his signature is not in the tower.  So, there is no concrete evidence of the original designer. 

RegardlesTower of Pisa in 1909:  Photographer unknownCredit: Photographer unknowns of who designed the tower, the construction was flawed from the beginning.   The Tower of Pisa took almost 200 years to complete.  It was built in three stages with the first stage beginning in August 1173.  In 1178, soon after the third story was being added, the tower began to sink.  The builders had set a thin foundation in weak, unstable subsoil of a dense clay mixture.  Hoping the soil would settle and stabilize the tower, architects halted the construction.  It was almost 100 years later when construction resumed.   

In 1272 when construction finally resumed, engineers built the upper floors with one side taller than the other to compensate for the tilt.  Construction continued until 1284 and then was halted again due to war.   The seventh floor was added in 1319 and the bell-chamber was finally added in 1372.  There are seven bells in the bell chamber, each tuned to a note of the musical major scale.  

Efforts to Fix the Tilt 

In 1838, architect Alessandro Della Geheradesca wanted visitors to see the base of the tower and decided to dig a walkway around the base of the tower.  This served to make the tower lean further which should come as no surprise.  Benito Mussolini was the next to “fiddle” with the tower’s structure.  He ordered the foundation to be filled with concrete, but the concrete only sunk further into the wet clay and did nothing to straighten thDoor to Leaning Tower of Pisa:  Photo by Lonewolf1976 at en.wikipediaCredit: Photo by Lonewolf1976 at en.wikipediae structure.  

At various times, the tower has been closed to visitors while engineers attempted to shore up the base.  Most efforts tried to lower the soil level on the higher side and in some instances, using counterweights to try to get the tower to shift.  In 1990 the Tower of Pisa was closed to the public and the bells were removed.  Soil was removed and the tower was straightened by a little over 17 inches to the same angle it was at in 1838.  The Leaning Tower of Pisa is angled at just shy of 13 feet past vertical.  It reopened to the public in 2001 and was declared stable.   In 2008 more ground was removed and the tower was declared stable once again.  

The Leaning Tower of Pisa as a Tourist Attraction 

Despite an order by the American military to destroy all towers during World War II because they cou6th Floor Stairs in Leaning Tower of Pisa:  Photo by Lonewolf1976 at en.wikipediaCredit: Photo by Lonewolf1976 at en.wikipediald be used to hide snipers, the Leaning Tower of Pisa was not bombed.  The Italian people are thankful of the reprieve.   A visit to Pisa, Italy isn’t complete without a trip to the tower.   Today, thousands of visitors climb the 296 steps to the top of the tower.  Only 30 people at a time at 40 minute intervals are allowed to go up the tower, lest they make it lean more. 

The Tower of Pisa is visited by approximately one million people each year.  Tours usually include the other two buildings located on the “Field of Miracles” as well: the Cathedral and the Baptistery.  The tower is made mostly of marble and the stairs inside are narrow and eroded; however, the view from the top is glorious.



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