The Tower of Pisa—Why Does It Lean?

By “Awake!” correspondent in Italy

CERTAIN well-known cities in the world owe their fame to some unique aspect of the city’s architecture or to an artistic masterpiece that has been handed down through history as an almost chance bequest. This is true of the town of Pisa, here in Italy. The name of this onetime maritime republic would be almost unknown today were it not for the famous leaning tower that has stood there for more than 700 years.

A visit to the Tower of Pisa is an unusual experience, and should you happen to visit it together with the “expert” who accompanied me on my visit, then you will enjoy it all the more. Let me tell you about it.

My First Impression

In all candor I must say that on my journey through central Italy I stopped off at Pisa only to see the tower. (I hope the townspeople will not be offended by my saying so.) Now I know that the town is worth a visit for many other reasons.

The tower is majestically set in the center of a large square, and its style is so extraordinary that it seems almost as if it were meant to lean over to defy the natural law of gravity. At first sight it is quite fascinating, and one gets the impression of being in front of a motionless giant poised on one leg. As I walked across the square I could not take my eyes off it. Gazing up at it from close quarters, especially on the leaning side, I felt as if it were about to fall on top of me at any minute. So much so that after a moment, looking furtively around to be sure nobody was watching, I walked—as nonchalantly as possible—to the other side. Now I could admire it at my ease.

The Guide

I was still intent on my elementary considerations, which had more to do with geometry than art, when my thoughts were interrupted by a voice with a typically Tuscan pronunciation.

“Fifty-four meters, six centimeters [177 ft., 4.3 in.].”

I turned around to thank whoever it was for this information and saw a young boy standing there. He was rather plump and had a very wide-awake look. I noticed the satisfied expression on his face and realized he had given me the answer to the question that had formulated itself in my own mind at that very moment.

“After people have been looking at it for about 30 seconds they usually wonder how high it is. You were perfectly in line with the average,” was the reply that made me blink. “Would you like me to guide you on a visit to the tower?”

I did not reply immediately but raised my eyes to have another look. Either it was the new angle of observation or else the invitation I had just received that made it look as if it were leaning over still farther.

“Oh, I see, you’re afraid!”

Maybe it was true, or maybe I just needed to be reassured. He seemed to understand this too, and before I knew it he was reeling off an interminable list of historical information that, on my checking up with the local guidebook, proved to be really accurate. I think he was trying to convince me that if the tower had been standing for such a long time it was hardly likely to fall down right now.

I was informed that the tower was built as the bell tower for the nearby cathedral and baptistry. It was designed by Bonanno Pisano, and the first stone was laid on August 9, 1173. After various interruptions the work was finished in 1370 by Tommaso di Andrea Pisano, but it appears that as early as 1298 there are records testifying to its leaning angle. The most reassuring fact is that up to now it seems to have resisted more than 100 earthquakes and the much more damaging effects of the second world war when nearby areas were under heavy bombardment and a few columns were blasted off by cannon fire.

The Problem of Its Leaning Angle

Faced with such accuracy of detail, I could only nod in agreement. But finally I plucked up courage to ask the question that had been bothering me from the beginning: “But . . . was it built with a lean or did it lean over afterward?”

Rather warily I awaited his reaction but was relieved to see by the thoughtful expression on his face that I had not asked an utterly silly question.

“As a matter of fact, that is exactly the question experts have been puzzling over for years. Some affirm that it was meant to lean over to give it an original touch. However, the majority maintain that it was the clayey subsoil impregnated with water from underground sources that gave way after the building had been initiated and that then the project was continued with all due precaution, in its leaning state. Nobody knows for sure exactly what happened . . . only the tower knows,” he said looking at it affectionately, “and that can’t speak to tell us about itself.”

Then he told me several legendary stories handed down through the centuries to support various theories. One story has it that the tower was built leaning over because a hunchback wanted it to be in his likeness. Another says it was tilted by the force of the wind. In the 18th century it was held that the tower was not leaning over at all but only seemed to do so as the result of an optical illusion.

My guide recited all this information with an air of having already repeated it a hundred times before and also with a certain complacency, so I was tempted to try to find a question he could not answer. I had a try: “Do you know how much it weighs?”

“Fourteen thousand five hundred tons,” came the answer, quickly followed up by: “At the top it has an inclination of four meters thirty-one centimeters [14 ft., 1.7 in.], which increases by .7 or .8 millimeter [about .03 inch] per year.”

Even this time he had been able to answer me. I decided to play my last card. “And when is it going to fall down?” I asked in rather an ironic tone.

“That’s obvious! When its center of gravity falls outside the area of its base. Over a certain inclination weights . . . ”

I realized that it was no use trying to win against this walking encyclopedia so I decided that it would be better to make serious use of him: “Can’t anything be done to stop the tilt from worsening?”

“Many solutions have been thought up and some have been tried out. In 1933 they even gave it 361 injections . . . ”

“They did what?” I exclaimed in surprise.

“Now, whatever did you think I meant . . . injections of cement . . . all around here, 93 tons of it all together.”

Of course, it was obvious, and I felt rather abashed by my first reaction. However, just to let him see that I was not wholly ignorant on the subject, I said I had read that in 1966 a world appeal had been made to stop the tower from leaning over any farther and that experts had been in general agreement about the need to stabilize the ground in the immediate vicinity. Some suggested that it should be prohibited to pump water out of the ground within a radius of one and a half kilometers (about 1 mi.); others thought that the inclination only worsens when the water table falls below 50 meters (164 ft.) and therefore the difficulty could be overcome by keeping the level stable by means of a system of pumps to take water out and pump it back in again according to the need of the moment.

The young boy also showed a knowledge of these details and continued the discussion by adding, “Then there are those eccentric ideas that some strange characters invent every so often.”

“Such as what?”

“Once an inventor suggested that the tower should be held up by steel cables, and another wanted to dig a tunnel underneath its foundations . . . ”

“What did he want to do that for?”

“Well . . . I’m not quite sure . . . ”

Finally I had found something he did not know! In any event, I had begun to like that young boy and would even be willing to go up the tower with him if he asked me again.

“Would you like to go up with me then?”

Naturally the question arrived punctually at the right moment as I almost expected it would. “All right, let’s go up,” I said without a moment’s hesitation.

Inside the Tower

It was nothing more than the cavity inside an enormous cylinder, essentially bare in comparison to the ornate lacy elegance of the outside graced with 207 columns harmoniously distributed in seven stories, with the story on top housing the bells.

With agility my guide climbed the steep stairways cut out of the walls. Seven stories—at each one we paused to wander round the circular walk and admire the panorama that fanned out beneath us. First we were looking over the spacious square, then over the massive buildings all round, then over the roofs and bastions of the walls in the distance. Finally from the top there was a stupendous view. To the north, the plain of Pisa delimited by the St. Giuliano mountains, behind which lies Lucca; to the east, the mountains of Pisa and the Arno valley; to the south the Pisan hills, and to the west, on that magnificent sunny day, the sea was visible together with the seaport of Livorno and the vast pine woods of St. Rossore.

My clever young guide’s eyes were shining as he pointed out the landmarks all around. Now he did not need to recite encyclopedic facts. He was carried away by a love for his native countryside and perhaps even for this very monument from the top of which we could see so far distant. Then, almost as if he had realized that he was forgetting himself, he was back in his role as the efficient guide again.

“Galileo Galilei, born at Pisa, conducted his experiments on the law of falling bodies from up here. As you can see, this is where the bells are housed, seven of them, weighing a total of 9,500 kilograms (20,944 lbs.). They are never rung out in continuous chimes, because their movement could cause vibrations dangerous to the tower. Each one has its own name . . . ”

He reeled off seven strange names with ease, but I was not listening anymore. I was just enjoying watching him playing the part of the official guide so well.

As we were going down the stairs I asked him for information about an eventual symbolic significance of the tower’s design and decorations, but he was rather elusive on the subject. Later, in an article by Dezzi Bardeschi (Psicon 1976) I read this curious explanation: “The seven stories (of the Tower) represent the seven ways to Christ, the seven phases in life and the seven harmonic spheres through which the soul must pass (with the help of the seven gifts of the holy spirit) to reach God.” Evidently medieval doctrine and philosophy were full of Oriental pagan beliefs that had become part and parcel of “Christian” culture.

My visit did not include the tower alone. I had read about the nearby monuments, the cathedral and the baptistry, also very beautiful from the outside and full of artistic masterpieces. With regard to these, my young guide was less prepared. As I looked at those, I saw that the boy was showing signs of impatience. It was time for us to part and so we reemerged into the open air where the sun was still shining on the velvety stretch of green grass. I said good-bye and offered him a small gift, which he had really more than earned, and then I watched him disappear, running and skipping, through the crowd.

Alone again, I gave a last glance at the graceful Leaning Tower and thought that, as many other beautiful old monuments, it stands in testimony of human skill and ingenuity, which gifts, rightly used, bring much more praise to the Creator than all the ringing of bells.