What is unique fact on Tower of Pisa?

One unique fact about the Tower of Pisa is that it leans at an angle of approximately 3.97 degrees. This tilt was not intentional and is the result of an unstable foundation that caused the tower to lean during its construction in the 12th century. Despite efforts to straighten the tower over the years, it continues to lean and has become a famous symbol of Italy.

The Tower of Pisa actually has five bells, despite its abnormal tilt. The bells range in size from the smallest, called "Pasquereccia," to the largest and oldest, known as "Assunta." Each bell has its own distinct tone and is used for various liturgical purposes. The tower's famous tilt did not prevent the installation of these bells, as they were designed to swing freely within the bell chamber.