The Tower of Pisa serves as the freestanding bell tower of the Cathedral of the Italian city of Pisa. It is placed behind the cathedral and is the third oldest structure in Pisa’s cathedral square after the Cathedral and the Baptistry. The tower is 183.27 ft from the low side and 186.02 ft from the high side. The width of the walls at the base is 13 ft and at the top 8 ft. Its weight is estimated at 16,000 tons. The tower has 296 or 294 steps; the seventh floor has two fewer steps on the north-facing staircase. Before the restoration work performed between 1990 and 2001, the tower leaned at an angle of 5.5 degrees, but the tower now leans at about 3.99 degrees. This shows that the top of the tower is displaced horizontally 12 ft 10 in. from where it would be if the structure were perfectly vertical.
The Tower of Pisa’s construction occurred in three stages across 177 years. The construction started on August 8, 1173 with the white marble ground floor of the bell tower. This was during a period of military success and benefit. This ground floor is a blind arcade decorated by spaced columns with classical Corinthian capitals. As the construction progresses to the second floor, the tower started sinking due to a small three-metre foundation, set in weak, unstable subsoil, a design that was doomed from the beginning. “Construction was subsequently halted for almost a century, because the Republic of Pisa was almost continually engaged in battles.