A brief look at the history of the Leaning Tower of Pisa

Monuments, a reminder of proud heritage or history as well as architectural wonders, they are present throughout the world. These sites are also a source of revenue for their respective cities or towns. Most of the monuments that fall under the category of architectural wonders are tourist places with a lot of monetary value, people tend to visit them to gaze upon the marvelous creations of man. One such monument is the leaning tower of Pisa. In 1990, the Italian government enlisted the help of the world’s finest engineers to stabilize the famous leaning tower. There have been many attempts in its 800-year history but this one was a race against time as the tower had already leaned on to a 5.5 degree whereas it had been projected that the tower would topple should it reach an angle of 5.44. It was a miracle that the tower was still standing but the crisis was still imminent.  

In the 12th century famous maritime town of Pisa, set about to turn its cathedral square to a magnificent landmark. So, in 1173, construction began on a free-standing campanile or bell tower and while the engineers and architects of the time were masters of their craft, they knew far less about the soil that they stood on. Pisa’s name had a Greek origin which meant “marshy land”, which clearly describes the clay, mud, and wet sand composition below the city’s surface. With a three-meter foundation to support the structure, it was no surprise that within less than five years the tower’s southern side began to sink beneath the surface. Such a mistake should normally have been a fatal flaw however, the construction halted for nearly a century while the tower was at the fourth story due to prolonged warfare that descended onto Pisa.  This long pause allowed the soil beneath the tower to settle and when the construction resumed in 1272, the workers saw the structure to be on slightly more stable ground. Under the guidance of architect Giovanni de Simone, the workers compensated the minor tilt by making the southern side slightly taller. But due to the extra weight of the masonry, the southern side continued to tilt even further. And by this time the tilt had increased to 1.6 degrees. For centuries engineers tried numerous strategies to address the lean, they even tried to dig a walkway to examine the sunken foundation but the removal of the supporting sand only worsened the problem, and thus with many such failed attempts all the engineers managed to do was worsen the ever-increasing tilt. However, in the years following WWII, researchers developed tests to examine the problem whereas, in 1970, engineers finally managed to calculate the center of gravity of the tower. Thus, with the modern tools at hand, the engineers could finally address the real problem and calculate different ways in order to stabilize the monument. They finally calculated the amount of excavation needed to stop the tilting of the monument and in 1992, a team drilled diagonal tunnels to remove 38 cubic meters of soil from underneath the tower’s north end, and temporarily balanced its weight with 600 tonnes of lead ingots and subsequently anchoring the base with steel cables. Thus, nearly six centuries after the completion of the tower, it had finally been straightened…to a tilt of about 4 degrees. The Italians didn’t want the tower to fall but they also didn’t want to lose the landmark’s most iconic feature. Today the tower stands at about 56 meters height and according to the estimates made by the engineers of the project, it should remain standing for another 300 years or so.

This is the tale of the monument that stands to show the beauty in imperfection. As Haruki Murakami wrote, “Don’t pointless things have a place too, in this far-from-perfect world”.