Where is the Leaning Tower of Pisa?

The tower is the freestanding bell tower of Pisa Cathedral. Construction began in 1173, and the tower started to tilt by the time builders reached the third storey, because it was built on soft clay and sand. War and interruptions meant it took about 199 years to finish, and builders tried to compensate by making upper floors slightly taller on one side. By 1990 the lean had reached about 5.5 degrees, and the tower was closed for more than a decade while engineers removed soil from beneath the higher side. It reopened in 2001 with its lean reduced to about 4 degrees, and it is expected to remain stable for at least 200 years.