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Why does the Leaning Tower of Pisa in Italy lean? It leans because of a mistake. It has leaned almost since the day the builders b    1  it.
In 1774, the people of Pisa in Italy wanted to build a bell tower. They wanted the tower to be the m    2  beautiful bell tower in Italy. The city needed a bell tower because the church(教堂) did not have o    3    . As soon as the first floor of the building was finished, the tower started to lean. Builders t    4    to make the building straight again as they added more floors, but the leaning tower got w   5    as the tower grew. It took about 180 years to finish the tower. Today, the leaning tower has eight f    6    It is 54.5 meters t    7    . And it leans almost 4 meters to one s    8   . The tower is also sinking(下沉) into the g    9  on which it was built. Every year, the tower leans a    10  1.7 cm.