Construction on the tower began in 1173 and was completed in 1360. Bonanno Pisano is thought to have originally designed the tower, but a succession of architects oversaw its construction over the amount of time it took to complete the project. Although the architects realized the design's inherent flaws in the early phases of construction, they continued with the project. With each successive story added to the tower, adjustments were made to the design in an attempt to redistribute the weight of the building and set it upright. Despite their efforts, the pitch of the tower was never corrected and the building retained--and became famous for--its tilt.
The tower stands at 187 feet and has eight stories. It contains seven bells. Constructed of white marble, it weighs more than 14,000 tons. Its famed tilt originates from the building's foundation; the soil on which is stands is incredibly soft and has been judged to be generally unsuitable for such construction.
In 1990, fearing that the tower was becoming increasingly unstable and would topple, the building was closed to the public for restoration. To stabilize the tower, a team of engineers corrected the tower's tilt by 17 inches. To do so, lead counter-weights were placed in sections of the tower, steel cables were attached to its facade, and tons of earth were strategically removed from underneath its base in an effort to realign the tower. More than a decade and $25 million later, the tower reopened to the public in 2001.
The Leaning Tower of Pisa is part of the larger Cathedral of Pisa complex (Piazza del Duomo), located within the Campo dei Miracoli (Field of Miracles). The entire area, including the Leaning Tower of Pisa, is a UNESCO World Heritage Site.
Because of the fragility of the tower, the number of visitors allowed inside the structure at a given time is limited. To climb the tower, visitors must sign up for a guided tour lasting about 30 minutes. Tour groups typically consist of 30 to 40 people. Reservations are recommended and may be made by calling 050 38 72 210 or visiting opapisa.it/boxoffice. Admission costs 15 euros (about $22).
