Tower of Pisa (Italy)
The Tower of Pisa is also known as the bell tower because it contains the bells of a giant cathedral built next to it. It is one of the Seven Wonders of the Ancient World. It is linked to the Italian scientist *Galileo Galilei* and his experiment on terrestrial acceleration. Located in the Italian city of Pisa. Its construction began in the year 1173 AD and was completed in the year 1372 AD, meaning its construction lasted 199 years.It consists of 8 floors, including the bell room, which includes 7 bells, each of which represents a different musical range from the other. Its height is 56.2 meters above the ground. Its mass is 14,500 tons. Its current inclination is 5.5 degrees. It has a staircase consisting of 294 steps, and is currently equipped with an electric elevator.This tower was supposed to be vertical, but it began to tilt shortly after starting to build it, but the architects continued building, so it was called the Leaning Tower of Pisa. Attempts were made to stop its tilt, but they did not succeed, and it is still in place until now. The secret of its tilt is attributed to the nature of the clay soil on which it was built and the various building materials. It was closed in 1990 AD and tourists were prevented from climbing it because it became vulnerable to collapsing at any moment. It was reopened in 2001 AD.It tended at a rate of (1-2) mm per year until it stopped in 2008 AD.Source: websites