1. The leaning tower of Pisa is located in the church square of Pisa, an ancient city in western Italy. It is the bell tower in the comprehensive building of Pisa Cathedral and the most famous building in the complex.

2. The leaning tower of Pisa was built in 1 174 and completed in 1350, all made of marble. At the beginning, the tower was erected, but when it was built on the third floor, because the foundation was not deep and the strength of the upper floor was low, the tower began to tilt and the project was suspended. Construction resumed after 1994, and a series of anti-tilt measures were strengthened. However, after the completion of the whole tower, the center of the tower top still deviates from the vertical center line. At present, the center point of the tower top ......