Tower of Pisa

The Leaning Tower of Pisa: History and Tilt Explained

The Tower of Pisa is recognized globally for its distinctive tilt, which has made it a renowned architectural wonder. In this article, we will delve into the reasons behind its leaning and shed light on this fascinating phenomenon.

Pisa, an important city in Tuscany, is the fifth most populous “comune” in the region, with a population of approximately 90,000 residents. As per a recent study by Il Sole 24 Ore in 2022, it ranks 10th in terms of quality of life among cities in Italy. The city is located in close proximity to the Arno river, the eighth-longest river in Italy, near its estuary at the Marina of Pisa.

The origin of the city’s name remains uncertain, with various legends suggesting a connection to the Greek city of Pisa in the regional unit of Elis in the Peloponnese. According to these legends, some of the Greek city’s inhabitants established a new city with the same name, Pisa, following the Trojan War.

Why the Tower of Pisa is Leaning

Surely at least once you have seen a picture of a person “holding up” the Tower of Pisa. It is a world-famous landmark, that took nearly two centuries to complete. Construction first started on August 9th, 1173, and was overseen by Pisan architect Diotisalvi, who was simultaneously working on the Battistero di San Giovanni in Pisa. However, there is some disagreement about the true authorship of the Tower, with Gherardi or Bonanno Pisano also being suggested as possible creators.

The construction of the Tower faced numerous challenges. At the halfway point of the third floor, work came to a halt following a partial collapse of the structure. The cause of this incident was due to the “pancone,” the clay ground underneath the Piazza dei Miracoli (also known as Piazza del Duomo), where the Tower stands, exhibiting plastic behavior (referred to as “normalconsolidata”) that ultimately gave way.

Only after a pause of 100 years, work on the Tower eventually resumed. In 1275, Giovanni di Simone and Giovanni Pisano attempted to rectify the lean of the building by adding three additional floors to the side opposite the Tower’s incline.

As time passed, the Tower’s tilt continued to get worse, and in the 17th century, it was discovered that the ground beneath it was saturated with water. They tried to remove the water, but it only made the tilt worse. Fortunately, today, the Tower is no longer in danger thanks to the installation of a massive 900-ton counterweight and other stabilization measures. Experts say that these changes will keep the Tower safe and standing for at least the next 300 years.

Ben Kerckx via Pixabay 

How much the Tower of Pisa is Leaning

The Tower of Pisa leans at an angle of 3.97 degrees, but back in 1990, the tilt had increased to 5.5 degrees. Interestingly, the Tower of Pisa is not the most tilted tower in the world. The Guinness Book of World Records gives that title to a 650-year-old church tower in northwest Germany.

The Tower of Pisa in the USA: Tower of Niles

Did you know that there’s a Leaning Tower of Pisa replica in the USA? The Leaning Tower of Niles is a structure located in Illinois that resembles the Tower of Pisa. It was constructed by industrialist Robert Ilg in the 1920s to accommodate two large outdoor pools. To preserve the natural beauty of the area, Ilg opted to build a replica of the Pisa Tower to conceal the reservoir.

The project began in 1931 and was completed in 1934, resulting in a smaller replica made entirely of reinforced concrete. In 1960, Ilg’s descendants donated part of the park to the city. However, the structure deteriorated over time, and it became challenging to maintain.

To remedy the situation, the Niles administration established a twinning pact with Pisa in the 1990s. In 1995, $1.2 million was allocated for a renovation project, as reported on the official website.

Cover Photo: Heidi Kaden / Unsplash