Although built to stand vertically, the tower began leaning soon being built in 1173 due to weak foundations and unstable subsoil. That is why it is called the Leaning Tower of Pisa.
The architectural style of the Tower mixes the Gothic elements of the belfry with the Romanesque style of the tower.
The Tower is made of white marble. It is over 15 metres round and 56 metres high and its weight is estimated at 14,500 tons. It has eight floors with an inside spiral staircase of 294 steps and it is well-known for its seven bells, one for each note of the musical scale.
It took near 200 years to build this tower, finished in 1372. Although the architects tried to counteract the inclination, it is still leaning nowadays, but because of the restoration made between 1990 and 2001, the tower now leans at an angle of 3.9 degrees instead of the former 5.5 degrees.
One of the most remarkable things related to the tower, apart from its inclination, is that Galileo Galilei is thought to have dropped two cannon balls of different mass from the tower to demonstrate that the speed at which any object falls was independent of the mass.
When I visited Pisa, I was stunned watching the Tower which did not fall despite its leaning and I took the typical photo everybody takes in which it seems you are holding it.