The construction of the famous Tower of Pisa in Italy was started in 1173 and finished in 139
Why was the Tower built
The Tower of Pisa is the belltower of the churches. The city of Pisa was at the beginning a simple but important Italian seaport. With its growth, so did its religious buildings.
Its fame and power grew gradually over the years, as the people of Pisa were involved in various military conflicts and trade agreements. The Pisans attacked the city of Palermo on the island of Sicily in 1063. The attack was successful and the conquerors returned to Pisa with a great deal of treasure.
To show the world just how important the city was, the people of Pisa decided to build a great cathedral complex, the Field of Miracles. The plan included a cathedral, a baptistery, a bell tower (the Tower of Pisa) and a cemetery.
Why does the Tower lean?
The leaning of the Tower of Pisa comes into the story in 1173, when construction began. Thanks to the soft ground, it had begun to lean by the time its builders got to the third story, in 1178. Shifting soil had destabilized the tower’s foundations.
Over the next 800 years, it became clear the 55-metre tower wasn’t just learning but was actually falling at a rate of one to two millimeters per year.
Today, the Leaning Tower of Pisa is more than five meters off perpendicular. Its architect and engineer tried to correct this by making the remaining stories shorter on the uphill side – but to no avail. It kept leaning more and more.
The lean, first noted when three of the tower’s eight stories had been built, resulted from the foundation stones being laid on soft ground consisting of clay, fine sand and shells.
The next stories were built slightly taller on the short side of the tower in an attempt to compensate for the lean. However, the weight of the extra floors caused the edifice to sink further and lean more.
Source: http://www.towerofpisa.org
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