Who built the leaning tower in pissa Italy?

The Leaning Tower of Pisa was built by a series of architects over the course of several centuries. Construction began in 1173 by the architect Bonanno Pisano, who designed the tower to be a freestanding bell tower for the Pisa Cathedral. The tower was originally designed to stand straight, but due to a combination of factors including unstable ground conditions and construction errors, it began to lean during construction. The tower continued to lean throughout its history, but its construction was ultimately completed by the architect Giovanni di Simone in 1350.