By the time builders had finished the third of eight planned stories about five years later, the tower’s foundation had begun to settle unevenly on the ground beneath it, a dense mixture of clay, sand and shells. As a result, the structure had begun to tilt visibly toward the south.
How Did the Leaning Tower of Pisa Lean?
The Leaning Tower of Pisa, an iconic landmark in the city of Pisa, Italy, is one of the most recognizable structures in the world. Built between 1173 and 1360, the tower has become a symbol of the city, and its iconic lean has intrigued millions of people for centuries. But how did the Leaning Tower of Pisa come to lean in the first place?
The most commonly accepted explanation for the tower’s tilt is that its foundation was not built on solid ground. Instead, the tower was built on an alluvial plain that was composed of clay, sand, and silt. This ground was too soft to support such a tall structure, and the tower began to lean soon after its construction.
The tilt of the Leaning Tower of Pisa has gradually increased over the centuries. In the 19th century, the lean was at its worst – it had reached 5.5 degrees. This caused alarm in the city of Pisa, and in 1934, a project to save the tower was initiated. The project included consolidating the foundation and reinforcing the structure with steel rods. This has helped to keep the tilt of the tower in check and has prevented it from leaning any further.