The Mystery Behind the Leaning Tower of Pisa’s Tilt

Tower of Pisa Engineering


Italy has always been notable for its stunning ancient architecture. From the Milan Cathedral to the Colosseum, each sculpture has been crafted with precision and delicacy. While all are magnificent, a few structures have been miscalculated. The most famous one is the Leaning Tower of Pisa, located in the Square of Miracles.

When engineer Bonnano Pisano first designed the Tower in 1174, there was no intention of the tilt. Instead, the Tower was built to house bells, a prominent feature within Catholic churches. One of the most famous events from the Leaning Tower was Galileo’s freefall experiment. Galileo dropped two spheres with different weights to see which would fall to the ground faster. Surprisingly, both spheres hit the ground at the same exact time. This is due to the constant acceleration of gravity at 9.8 m/s2. Galileo’s experiment was the foundation of kinematics in the physics world.

What makes The Leaning Tower of Pisa lean? Simply put, every standing structure requires a stable base. Unfortunately, Pisano chose the wrong site for construction. The Tower is built on soft ground composed of clay, sand, and shells. Also, due to much water underground, Pisano was only able to dig 10 feet into the ground. The unsteady base has caused the tower to sink into the ground at an angle over time.

Today, the Tower stands at 191 feet with a tilt of 4 degrees. There are seven bells attached at the top of the Tower: L’Assunta, Il Crocifisso, San Ranieri, La Terza, La Pasquereccia, Il Vespruccio, and Dal Pozzo. These bells total a whopping 23,150 pounds. The Tower was built with respect to European Romanesque architectural style, which is characterized by semi-circular arches. This famous structure has expanded Pisa’s economic prosperity by attracting over a million tourists each year.

The architects and engineers of the Leaning Tower of Pisa aren’t alone. There have been several large structures that have been miscalculated in the past. Some examples are:

  • The Giant Wild Goose Pagoda
  • The Belfry of Bruges
  • Der Neue Zollhof
  • Puerto Morelos Lighthouse
  • The Millennium Tower

At CEDARVILLE Engineering Group, LLC (CEG), we strive to provide excellent service that is beneficial for you. Call us at 610-705-4500 or email to find out more.

By: J. Auerbach

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CEDARVILLE Engineering Group, LLC (CEG)
159 E. High Street, Suite 500, Pottstown, PA 19464
P:610-705-4500 F: 610-705-4900
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