In order to give the cathedral a bell tower this wonderful monument was started in 1173. Its leaning was almost immediate and was caused by the type of ground the tower is sitting on: a composition of clay and soil which is based on 40 m deep sand and clay layer. The construction was stopped and then resumed with many failed solution trying to solve its slope. There has been one recently which apparently has counterbalanced the leaning of the tower. It was finished in 2001 and permitted visits to be resumed. To prevent the building from further inclination the bells the tower affords have not tolled for over 50 years now.
The edifice was designed in Romanesque style and at present due to its inclination only 40 visitors can climb it in each ascent. Tickets can be purchased on the internet, by telephone or in the booth in the Piazza dei Miracoli. You should make reservations as unavoidable queues of 45min-2hours are the corollary if you do not. The reservation tickets are €15. Tickets bought in advance are €17 and none is refundable or exchangeable. Restrictions to visitors are as follows: They have to be over 8; bags are not allowed to be carried and they have to be ready for good leg stretching as there are 300 steps to go up, therefore being fit is almost a need.
The Leaning Tower is not the only one building which has surrendered to inclination. The Chiesa di San Nicola (Via Santa Maria) and the Chiesa di San Michele degli Scalzi on the namesake street are also at a slope.
There was a project to build a new glass and steel leaning tower of 57m of height housing offices and apartments. This undertaking was planned by Dante Oscar Benini to begin in 2004 and be finished in 4 years. However, the project attracted disapproval.