1. The soil layer under the foundation of the leaning tower of Pisa is alternately formed by all kinds of soft silt and extremely soft clay deposits, and it is a groundwater layer at a depth of about one meter. The leaning tower of Pisa has just been built because of its foundation.

2. The leaning tower of Pisa was built in August, 1 173. It is the independent bell tower of Pisa Cathedral in Italy, located in the Miracle Square in the north of Pisa in Tuscany, Italy.