英語翻譯
The Tower of Plsa was built to be the most beautiful bell tower in all of Italy.It is the bell tower for Poia Cathedral.However.not only is the marble tower beautiful,it is perhaps the strangest tower in the world.It leans to one side and looks like it is going to fall over.
The building of the tower began in August 1173 and took nearly two hundred years to complete.Nobody is certain who designed the tower,but for many years it was said that Bonanno Pisano was the architect.In 1319,all the floors were finished and years later,work eventually began on the bell chamber at the top.It was officially opened after 200 years of construction.The tower has eight floors.It is 54.5 metres tall with 294 steps up to the bell chamber.From the top,there is avery beautiful view.Italian scientist,Galileo,once did his famous experiments about gravity and falling objects from the top of the tower.
Why does the tower lean?In fact,it was already leaning while they were building it.As soon as three floors had been built,by 1178,it began to lean as the ground beneath it sank.The builders tried to make the tower straight again as they added more floors,but the lean only got worse as the tower grew.It continued to lean by about 1 millimetre every year until finally,on 7 January 1990,it was closed to the public.For ten years,the rescue of the tower was a serious problem.The top was leaning over by 5 metres to the south and if its movement was not stopped,the tower would one day fall over,Measurements taken in 1911 estimated that the tower would collapse by 2050,if not sooner,After 10 years of hard work,it was officially reopened on 16 june 2001.However,it was not opened to the public intil the end of 2001 and even now,the umber of visitors is restricted.It is now safe for the next 300years because engineers have reduced the lean by 50 centimetres to give it the same lean that it had in 1838.