Leaning Tower of Pisa

The Leaning Tower of Pisa (Torre Pendente di Pisa in Italian) is a medieval bell tower and tourist destination located in Pisa, Italy. The Tower is most famous for its lean, which was formerly 5.5 degrees (approximately 15 feet or 4.5 meters), but has since been reduced.

## History

### Construction

Construction began on the Tower on August 9, 1173, and was intended "to stand 185 feet (56 metres) high and was constructed of white marble." However, due to unstable soil, "The Tower started to lean about five years into construction," and was paused in 1178 due to Pisa going to war with the city-state of Genoa. Work on the Tower didn't continue until 1272, and was declared "finished" in 1372.

#### Architects

While it is unknown who exactly created the Tower, the first iteration of work was mostly credited to Bonanno Pisano and Gherardo din Gherardo. The second iteration of work was credited to Giovani di Simone, and the architect who finished the Tower was Tommaso Pisano.

### The Tower Now

Due to its lean, the Tower slowly continued to fall, with some engineers measuring the Tower's movement in the 1910s and 1920s, and others trying to fix it in the 1930s and 1960s. The Tower's heavier bells were silenced around this time, due to fears that they would make the Tower's lean worse. It was only until 1989 was it clear "that the southward lean was taking an inexorable path towards failure." From 1990 to 2001, the Tower was closed to the public for stabilization efforts, and was reopened afterwards. In 2008, engineers estimated that the tower would last for at least 200 more years. However, in 2018, the BBC reported that the Tower is slowly straightening itself.

## References

1. ↑ 1.0 1.1 1.2 1.3 Encyclopedia Britannica. Editors of Encyclopedia Britannica. "Leaning Tower of Pisa." https://www.britannica.com/topic/Leaning-Tower-of-Pisa
2. ↑ 2.0 2.1 BBC News. November 22, 2018. "Leaning Tower of Pisa 'now leaning less'." https://www.bbc.com/news/world-europe-46300789
3. ↑ Thomas Telford Ltd. 1999. Potts, David M., et al Lidija Zdravkovic. "Finite Element Analysis in Geotechnical Engineering: Application." pg. 254.
4. ↑ Leaning Tower Pisa. Facts. "WHY is the Tower of Pisa Leaning?" https://leaningtowerpisa.com/facts/why-is-pisa-tower-leaning
5. ↑ 5.0 5.1 History.com. Pruitt, Sarah. December 3, 2015. "Why does the Leaning Tower of Pisa lean?" https://www.history.com/news/why-does-the-leaning-tower-of-pisa-lean
6. ↑ 6.0 6.1 6.2 Leaning Tower Pisa. Facts. "WHEN did the Leaning Tower of Pisa Start to Lean?" https://leaningtowerpisa.com/facts/when-pisa-tower-started-leaning
7. ↑ Leaning Tower of Pisa. "Tower of Pisa Historical Facts." https://www.towerofpisa.org/tower-of-pisa-historical-facts/
8. ↑ Cool Old Photos. "The Leaning Tower of Pisa in the 1890s – Reopened to the Public in 2001." https://coololdphotos.com/leaning-tower-of-pisa-in-the-1890s/
9. ↑ 9.0 9.1 Smithsonian Magazine. Ault, Alicia. March 9, 2015. "Ask Smithsonian: Will the Leaning Tower of Pisa Ever Topple?" https://www.smithsonianmag.com/smithsonian-institution/will-leaning-tower-pisa-topple-180954493/
10. ↑ Leaning Tower Pisa. Facts. "HOW was the Leaning Tower of Pisa stabilized?" https://leaningtowerpisa.com/facts/how-pisa-leaning-tower-was-stabilized