The Leaning Tower of Pisa, located in Pisa, Tuscany, Italy, is one of the most famous leaning towers in the world. It was built as a part of Pisa Cathedral in 1173, but it started to lean during construction and was completed in 1360. How does this tower remain standing even though it is still leaning? In this article, we will explore the history, structure, causes of leaning, and preservation methods of the Leaning Tower of Pisa.

History of the Leaning Tower of Pisa

The Leaning Tower of Pisa is the bell tower of Pisa Cathedral, built in the Romanesque style with eight levels. The tower is 55.86 meters tall and has 297 steps. Its weight is approximately 14,453 tons, and the average stress applied to the ground is 50.7tf/m2.

Construction of the Leaning Tower of Pisa began on August 9, 1173. At the time, Pisa was a major port city on the Mediterranean Sea with abundant financial resources. Pisa wanted to build a structure that would symbolize their glory and wealth, which led to the decision to build Pisa Cathedral, the Leaning Tower of Pisa, and the baptistery.

The Leaning Tower of Pisa was designed by architect Bonanno Pisano, but he died before its completion. Construction was carried out in three phases: the first phase from 1173 to 1178, the second phase from 1272 to 1278, and the third phase from 1360 to 1372.

During the first phase, the first three levels of the tower were completed, and it started to lean. This was because the ground in Pisa was composed of wet sand and mud, unsuitable for supporting tall buildings.

The second phase completed seven levels of the tower. To correct the leaning angle, they made the side that was leaning higher. However, this method further shifted the center of the tower and intensified the lean.

In the third phase, the top of the tower and the bells were installed, again making the leaning side higher. As a result, the tower was completed at a 1.6-degree tilt.

The name Pisa is believed to have originated from the Greek word for "marsh." When constructing the Leaning Tower of Pisa, they dug only 3 meters into the ground, which was too shallow to withstand the weight of the building. Consequently, the south side of the tower subsided, causing it to lean.

Structure of the Leaning Tower of Pisa

The Leaning Tower of Pisa has eight levels, each with different decorations and structures.

● The first level of the tower is composed of 15 arches and serves as the entrance to the tower.

● The second level of the tower has 30 arches and is the heaviest level of the tower.

● From the third to the seventh level, the tower is composed of 8 arches, each level with different shapes of columns and decorations.

● The eighth level is the bell tower, and 7 bells were installed.

● There is a hole at the top of the tower for astronomical observation.

Although the Leaning Tower of Pisa is a leaning tower, its interior remains vertical. This is because the steps inside the tower are curved towards the leaning side.

The tower has a total of 297 steps, allowing visitors to climb from the first to the seventh level. The eighth level has no steps, so visitors need to use a ladder. Inside the tower, there are information boards about its history, structure, and preservation methods.

Causes of the Leaning Tower of Pisa and Preservation Methods

The Leaning Tower of Pisa began to lean during construction because the ground in Pisa was uneven and soft, unable to support the weight of the building. The ground in Pisa is composed of wet sand and mud, causing the south side of the tower to sink more, leading to the lean. At the time, the tower increased its angular momentum, making it lean faster.

This phenomenon repeated in a vicious cycle, causing the tower to lean even further. The Leaning Tower of Pisa became a world-famous landmark, but it also faced the risk of collapse. The tower's tilt increased to 5 degrees, and it was in danger of collapsing at any time. To prevent this, numerous preservation efforts were undertaken.

In 1964, an 800-ton iron counterweight was installed at the top of the tower, and an inclinometer was installed in 1979 to measure the tower's tilt. Construction of the tower was halted in 1990, and it was closed to the public. In 1993, 38 cables were connected to the north side of the tower to pull it back. In 1995, a 600-ton counterweight composed of lead and iron was installed on the south side of the tower. In 1999, 70 tons of soil were removed from the south side of the tower to reduce the lean.

These efforts reduced the tower's tilt to 3.97 degrees and increased its stability. The tower reopened to the public in 2001, and preservation efforts were completed in 2008. Currently, the tower is expected to remain stable for another 300 years.

How to Visit the Leaning Tower of Pisa

The Leaning Tower of Pisa is a UNESCO World Heritage Site and is visited by numerous tourists. To visit the Leaning Tower of Pisa, reservations are required.

The Leaning Tower of Pisa can accommodate 50 visitors at a time, with 15-minute intervals between each group. Entrance fees for the Leaning Tower of Pisa are 20 euros, and the combined ticket is 27 euros.

The Leaning Tower of Pisa is open from 9:00 AM to 6:00 PM, but it is closed on December 25th and January 1st.

The Leaning Tower of Pisa is a 10-minute bus or taxi ride from Pisa Airport and a 20-minute walk from Pisa Central Station.

Here are some tips to keep in mind when visiting the Leaning Tower of Pisa:

• Wear comfortable shoes as the steps in the tower are narrow and high.
• Be careful as the steps inside the tower are tilted, and those who experience motion sickness or are physically weak should be cautious.
• Bring your camera as you can enjoy the panoramic views of Pisa from the top of the tower.
• Try the famous pose of taking a picture with you and the tower near the tower.

Official website of the Leaning Tower of Pisa

www.opapisa.it

Fun Facts about the Leaning Tower of Pisa

● The Leaning Tower of Pisa was originally white, but it turned yellow over time. This is because the marble used for the tower oxidized in response to air and water.

● During World War II, the Leaning Tower of Pisa was used as an observation post by the German army. They placed a red cross on the top of the tower to avoid bombing by the American forces.

● It is said that Galileo Galilei conducted experiments on gravity at the Leaning Tower of Pisa in 1589. Galileo is said to have dropped objects of different weights from the top of the tower to prove that they fall at the same speed regardless of weight. However, this did not actually happen, but was mentioned in a book written by one of Galileo's students.

● In 2008, David Blaine, an American magic star, performed a magic trick where he made the tower disappear. Blaine stood in front of the tower, spread a large cloth, and claimed that the tower disappeared when he removed the cloth. However, this was just an illusion created by covering a building behind the tower with a cloth shaped like the tower.

Conclusion

This concludes our blog post about the Leaning Tower of Pisa. The Leaning Tower of Pisa is a leaning tower, known as one of the wonders of the world. Visiting the Leaning Tower of Pisa allows you to learn about its history, structure, and the secret behind its lean. The Leaning Tower of Pisa is a World Heritage Site and requires preservation and management.