Thesis The Tower of Pisa known globally due to its mysterious lean which is nearly four degrees, brought about by an unstable foundation. Focusing on the details regarding the architect, construction history, earthquake survival, entry into Guinness world records and technical information of the Tower will help in understanding the Tower. Caprili, Silvia, Federico Mangini, Sandro Paci, Walter Salvatore, Marco G. Bevilacqua, Ewa Karwacka, Nunziante Squeglia, Riccardo Barsotti, Stefano Bennati, Giuseppe Scarpelli, and Paolo Iannelli. "A Knowledge-Based Approach for the Structural Assessment of Cultural Heritage, a Case Study: La Sapienza Palace in Pisa." Bulletin of Earthquake Engineering: Official Publication of the European Association for Earthquake Engineering. 15.11 (2017): 4851-4886. Print. Caprili et al. are authors with diverse backgrounds in history and assessment of the structure. In the article, Caprili et al. argue that the tower is believed to have started leaning during the construction period in the 12th century, because of soft ground that could barely support the weight of the structure. This article is important in researching the leaning of the Tower. The leaning worsened at its completion in the 14th century and is said to have