The Leaning Tower of Pisa is an eight-story, 51-foot (15.5 meter) tower standing in Pisa, Italy that, from the seventh floor, leans about 14.5 feet (4.4 meters) off center. It was built as a bell tower in the 12th century, and started to lean to the north during construction. Attempts correct the lean during further construction caused the tower to tilt toward the south instead. Further attempts to correct the lean may have almost caused the tower to collapse. Nevertheless, the Leaning Tower of Pisa’s lean continues to attract tourists from all over the world.
Construction on the tower was started in 1173 by Bonnano Pisano. After five years, with the construction of the third story, the tower started to lean to the north. Construction was abandoned in order to allow the ground to settle and to allow Pisa to concentrate on a war it was involved in. About 90 years later, three more stories were built by Giovanni de Simone, whose work caused the tower to start leaning to the south. In 1372, almost 200 years after construction started, the belfry was put on by Tommano Simone.
Over the years, many people have attempted to correct the tower’s lean. Giovanni de Simone tried to stop the lean by building the floors parallel to the ground rather than in proportion to the rest of the building. This correction instead caused the Leaning Tower of Pisa to tilt to the south instead of to the north. Another attempt to correct the lean, ordered by Benito Mussolini, was to drill holes in the foundation and fill them with concrete. That correction only made the tower sink further.
Modern attempts to stabilize the structure have caused the Leaning Tower of Pisa to sink further. In 1995, architects tried to freeze the ground with liquid nitrogen so they could work on the tower without the soil collapsing. The attempt was to try and use metal rods to stabilize the tower. Freezing the ground actually allowed for holes in the soil around the tower. This attempt caused the tower to lean as much as it would have in two years.
The Leaning tower of Pisa was eventually stabilized, however. In 1999, John Burland, a British engineering professor, suggested removing soil from the higher part of the building. The restoration efforts were finished in 2001. At the end of this construction, the tower leaned as far it did 1838.