August 9, 1173 Leaning Tower of Pisa

Italy has no fewer than ten towers with an other than perpendicular relationship to the ground. Three in Venice, one each in Bologna, Caorle, Burano and Rome and two others, in Pisa.

In the world of architecture, a campanile [kampəˈnēlē] is a tower, usually built beside or appended to a larger structure and most often associated with Italian architecture. Since the 19th century, such structures have served as clock or bell towers for factories, colleges and apartments. Earlier examples are mostly associated, with churches.

The earliest Campaniles date to the 5th and 6th centuries, such as those in Classe (c. 532–49) and Ravenna (c. 490). The most famous is the leaning tower of Pisa, construction for which began on this day, in 1173.

Standing 55.86 metres (183.27 feet) on the low side and 56.67 metres (185.93 feet) on the high side and weighing in at 16,000 tons, early planning began on January 5, 1172 when the widow Donna Berta di Bernardo bequeathed 60 Soldi for the purchase of stones, to form the foundation.

Footings were laid on August 9 of the following year, the distinctive white marble of the ground floor begun, five days later. The lean set in in 1178 with the construction of the second floor due to shallow foundations, and unstable subsoil.

Italy didn’t become a nation in the modern sense, until 1861.  In the 12th century, Pisa was an independent city-state, often at war with other such polities, on the Italian peninsula.  Construction halted for nearly a century while Pisa made war on Genoa, Lucca and Florence allowing the soft soil, to stabilize. Otherwise, the thing would surely have toppled.

Interior view of the leaning tower of Pisa

Construction unfolded in three major stages over 199 years. Engineers built the upper floors taller on one side than the other, to compensate, for the tilt. It’s why the thing appears curved, at certain angles. The last of seven bells representing the seven notes of the major musical scale was installed, in 1655.

Surprisingly, the Campanile in Pisa is not the only leaning tower in Italy. It isn’t even the only one, in Pisa. Italy has no fewer than ten towers with an other than perpendicular relationship, to the ground. Three are in Venice, one each in Bologna, Caorle, Burano and Rome and two others, in Pisa.

The Italian polymath Galileo Galilei was from Pisa and famously dropped two cannonballs of different sizes from the tower, to illustrate the Law of Free Fall. Galileo ended his life under house arrest for the heretical notion that the earth, revolved around the sun. The cannonball story was published long after his death, told in a biography written by Galileo’s student and personal secretary, Vincenzo Viviani. To have published such a work earlier would have significantly increased the chances, of the author’s burning at the stake.

Plaque memorializing the experiments, of Galileo

Four severe earthquakes have stricken the region since 1280 but the leaning tower, stands secure. Ironically, the soft soil which produced the lean in the first place has dampened the vibration so the tower, remains still.

The leaning tower was suspected of harboring German observers during World War 2 and US Army Sergeant Leon Weckstein was sent, to investigate. Weckstein was so impressed with the beauty of the cathedral and its campanile he refrained from calling, an artillery strike.

In 1989, the abrupt collapse of the civic tower in Pavia resulted in 280,000 cubic feet of brick and granite rubble leading to the closure to visitors, of the leaning tower of Pisa.

Civic tower of Pavia

Over the centuries, efforts to compensate for the lean have accomplished little. Some even made the problem, worse. More recent innovations have reduced the lean by some 17½-inches including counterweights, excavations and cables. These and the removal of bells to reduce weight have returned the tower to its 1838 position. In 2008, engineers declared the tower stable, for 200 years. In the end, the Italian government has no desire to straighten the thing, all the way. The leaning Tower of Pisa is far to great a draw, for the tourist dollar.

Lead counterweights, installed in 1998.
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