Leaning Tower of Pisa (in Italian: Torre pendente di Pisa) or commonly called the Tower of Pisa (La Torre di Pisa) is a bell tower of a cathedral in Pisa, Italy. The tower is located behind the cathedral and is the third structure in the Campo dei Miracoli (miracle) of Pisa.

Although the original plan is built vertically, the tower began leaning to the southeast soon after construction in the year 1173, due to imperfect foundation.

Height of the tower is 55.86 km from the ground on the lowest side and 56.70 m on the highest side. The width of the building's base is 4.09 m and width of the top 2.48 m. Weight tower is estimated to 14.500 tons and has 294 steps.

Construction of the Tower of Pisa was built in three stages, which takes about 200 years. Construction of white marble on the first floor began on August 9, 1173, at the time of military success and prosperity of Italy. The first floor is surrounded by pillars and although some oblique position, but still hold for many centuries.

There is controversy surrounding the identity of the architect who built the Leaning Tower of Pisa. For years, the design is believed to be made by Guglielmo and Bonanno Pisano, a local artist famous in the 12th century, famous for its bronze work, especially in his Pisa Duomo.

Bonanno Pisano left Pisa in 1185 and moved to Monreale, Sicily, but then come back and die in the land of his birth. His grave was found at the base of the tower in 1820.

The tower was first slash after the third floor was built in the year 1178, due to amblasnya foundation three feet deep, due to ground movement. This means that the design of the tower has been disabled since the beginning.

Construction was suspended for nearly a century old, because the citizens of Pisa almost involved war with Genoa, Lucca and Florence. During the period of 'rest', the land beneath the structure has been re-stabilized. And in the year 1198, fitted for hour while the building was still unfinished.

In 1272, construction was resumed by Giovanni di Simone, architect of the Camposanto. The fourth floor was built to compensate for the slope of this tower. The rebuilding was stopped in 1284, when Pisa conquered by the Genoese in the Battle of Meloria.

Construction of the bell tower was not completed until 1372 halted. After that, Tommaso Andrea Pisano in the successful completion of the elements of the Gothic tower, with a touch of style of Rome. There are seven bells in the tower, each of which represents a note on the tone. The biggest bell installed in 1655.