Who built the leaning tower in pissa in Italy?

The Leaning Tower of Pisa was built by the Italian city of Pisa, with construction beginning in 1173 and concluding in 1372. The architect traditionally credited with its design is Bonanno Pisano, though the project involved multiple architects over the years. The tower was initially intended as a freestanding bell tower for the nearby cathedral. Its famous lean occurred due to unstable foundation soil.