On 9th August 1173, work began on the construction of a freestanding bell tower for the Cathedral in Pisa. The famous lean started during the building process.
The tower (Torre Pendente di Pisa) has made the town famous and is one of Italy’s most popular tourist attractions. The tilt began during the building process.
Inadequate foundations on ground that was too soft on one side is thought to be cause of the lean. The tilt became worse over the years and restoration work had to be carried out at the end of the 20th century amid fears the tower would collapse.
The identity of the architect responsible for the design is not clear. The problem with the structure began after work had progressed to the second floor in 1178. It is believed the tower would have toppled had construction not been halted for almost a century while Pisa fought battles with Genoa, Lucca and Florence. This allowed time for the soil beneath the tower to settle.
When construction resumed in 1272, the upper floors were built with one side taller than the other to compensate for the tilt. The seventh floor was completed in 1319 and the bell chamber added in 1372.
Read: Italy’s other leaning towers
Efforts to fix the Leaning Tower of Pisa
Italian leader Benito Mussolini considered the flawed tower antithetical to Fascist ideals. In 1934, engineers tried to right it by injecting almost 200 tons of cement into the base. The “fix” actually added a tenth of a degree to the tilt.
At its most extreme the tower leaned at an angle of 5.5 degrees. However, since the restoration work between 1990 and 2001 the tower leans at about 3.99 degrees.
The tower was closed to the public in 1990 while work was carried out to straighten it. The tower was effectively returned to its position in 1838.
It was reopened to the public in 2001 when it was declared that it would be stable for another 300 years. In 2008, engineers announced that the tower had stopped moving for the first time in its history.
In 1987, the 60-metre tower was included in the Piazza del Duomo UNESCO World Heritage site along with the neighbouring cathedral and baptistery.
