Everything Everywhere Daily: History, Science, Geography & More - The Leaning Tower of Pisa

Episode Date: May 5, 2021

In 1173, the Italian city of Pisa was on top of the world. They were a significant commercial power in Italy, commanded a sizable Mediterranean fleet, and wanted to demonstrate their power to the world. It had built a marvelous cathedral, and comparable baptistry and they decided to complete the complex by building a bell tower. However, that didn’t quite go as planned. Learn more about the Leaning Tower of Pisa on this episode of Everything Everywhere Daily. Learn more about your ad choices. Visit megaphone.fm/adchoices

In 1173, the Italian city of Pisa was on top of the world. They were a significant commercial power in Italy, commanded a sizable Mediterranean fleet, and wanted to demonstrate their power to the rest of the world. They had built a marvelous cathedral and a comparable baptistry, and they decided to complete the complex by building a bell tower. However, that didn't quite go as planned. Learn more about the Leaning Tower of Pisa,

one of Italy's most iconic structures on this episode of Everything Everywhere Daily. What if your perceptions about the past were wrong? ThruLine is a podcast that takes you back in time to uncover the parts of the story that may have gone unnoticed. It effectively turned day into night. And how it shaped the world now. Time travel with us every week on the ThruLine podcast from NPR. This episode is sponsored by rerouted. Let's face it, outdoor gear can be expensive.

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Or click on the link in the show notes. Medieval Italy was known for its powerful Italian maritime republics. In particular, there were four such republics that were the wealthiest and most powerful. Venice, Genoa, Amalfi, and Pisa. Pisa reached the peak of its power in the 11th century. During this time, they were often battling with Saracens, which was a medieval term for Arab Muslims. The Saracens had bases on the island of Corsica and would clash with Pisa on the seas.

Pisa also removed the Genoese from Sardinia and conquered Carthage in North Africa. They also took the city of Palermo and Sicily from the Saracens, and with the gold they looted, they were able to use the money to get something nice. So in 1063, they began to construct the Pisa Cathedral. The Pisa Cathedral is a really remarkable building. It was a Romanesque cathedral, which, if you remember back to the episode I did on cathedrals, was the style before Gothic cathedrals. The cathedral itself was uniquely built outside the ancient walls of the city, which in itself was a show of strength.

It was their way of telling the world that they weren't afraid of being attacked. In 1092, the cathedral was declared the seat of the Archbishop of Pisa, and in 1118 it was consecrated by the Pope. The area immediately around the cathedral became known as the Piazza de Miracoli, which means the plaza Plaza of Miracles. A second building, a baptistery, was begun in 1152 and completed in 1363. The final building in the Piazza de Miracoli was to be the Campanile, or the bell tower. In 1172, a widow by the name of Donna Berta D. Bernardino left 60 silver pieces for the creation of the base of a bell tower in her will, and in 1173, construction began. The tower was designed to be eight stories tall and was to be built out of marble.

The original architect of the tower isn't actually known. There are no surviving documents from the period when the tower began construction. Whoever designed the tower made a very critical error from the outset. In 1178, only five years after construction began, and when they finished the second floor, it became obvious there was a problem. The tower, what little was actually built, started to sink. The tower had fundamental flaws which really couldn't be fixed. Its foundation simply wasn't thick enough, and it was built on a site.

subsoil that was too soft. Pisa was located on the banks of the Arno River, and there's a great deal of clay and silt below the ground. If they had compensated for this at the start, or if they had built it in a slightly different location, we would just know it as the Tower of Pisa, and probably not even that. In 1178, after the second story was built, construction was halted for almost a century. This halt in construction, strangely enough, almost certainly saved the tower. The reason for the lengthy pause in construction had nothing to do with the tower itself. Pisa found itself in conflicts with their neighboring city states in Italy, primarily Genoa, Florence, and Luca. The reason why this pause saved the tower is that it allowed the soil underneath the foundation of the tower

a chance to settle for almost a century. Construction began again in 1272. To compensate for the tilt in the tower, the new architect built the next floor such that one side was taller than the other. If you look very closely at the tower today, you can see that it's actually slightly curved. This was the result of this architectural decision. Twelve years later, in 1284, the construction was halted again when Pisa lost a war with Genoa. In 1319, the seventh floor was finished, and finally, in 1372, the bell chamber was completed, finishing the tower. It took a total of one hundred and ninety-nine years for the tower to be built. The most famous event which took place in the tower was undoubtedly the experiments by Galileo Galilei. He lived in Pisa from 1589 to 1592, and during

that time, he conducted an experiment where two cannon balls of different weights were dropped from the tower at the same time. They reached the ground simultaneously, proving that the acceleration of each cannon ball from gravity was the same and independent of their weight. In World War II, American forces thought that the Nazis were using the tower as an observation post. An American Army Sergeant, Leon Wexstein, was sent to observe, and he thought that the cathedral and the tower were so beautiful, he refused to call in an artillery strike, which would have destroyed the tower. Its famous lean was a feature of the tower from the outset.

However, it didn't lean nearly as much as it does today. Just before the first major pause in construction, when the second floor was built, the tower leaned one-tenth of a degree to the north. When the seventh floor was built, it was leaning one degree to the south. Over the centuries, the tower never stopped slowly leaning further and further off vertical. By the 20th century, the tower was leaning almost six degrees from vertical, and the top of the tower was a full 15 feet from where it should have been. On March 17, 1989, the Civic Tower in the town of Pavia in Italy, collapsed, killing four people.

This shocked the Italian government into taking action to save the tower in Pisa. If the lien kept getting worse, eventually the tower was going to collapse. In January 1990, the tower was closed to the public and a campaign was started to reverse the lien in the tower and try to save it. Over 70 metric tons of soil were removed from the north end of the tower, creating spaces in which the tower would be able to compress over time, allowing the tower to tilt back north a little bit. They also stacked tons of lead on the north side of the tower to serve as a counterweight to try and correct the tilt. From 1990 to 2001, the tilt on the tower was reduced by 45 centimeters or 18 inches. It now only leans four degrees off of vertical, which is where the tower was in the early 19th century.

After the stabilization efforts, engineers denounced that the tower should be safe for another two to 300 years. In 2008, they announced that for the first time, in the tower's history, it had stopped moving. You might be asking, why don't they just fully straighten the tower? Well, the answer is money. People come to Pisa to see a leaning tower, not a straight tower. They want the tower to lean a little, but just not so much that it would collapse. If you visit Pisa, like most people, you should certainly go see the tower. But what you might realize once you're there is that the cathedral itself, which is usually overlooked, is really the highlight of the trip. Yeah, the leaning tower of Pisa is, I

iconic and it's leaning, but that's about it. The most entertaining thing is watching all the tourists taking photos of themselves trying to hold up the tower. Eventually, someday, the leaning tower of Pisa will probably collapse. It probably won't happen in any of our lifetimes. But unless some future technology can solve the fundamental problems which have been in the tower from the start, then the leaning tower of Pisa probably has a finite lifespan. The associate producer of Everything Everywhere Daily is Thor Thomas.

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