The Leaning Tower, Pisa’s most famous landmark.
Begun in 1173 on sandy silt subsoil, it started to tilt 5 years later, after the third floor was
being added. The building was left for a century to allow the foundations to stabilize and stop the
building from collapsing. Construction resumed in 1272, with the upper floors built with one side
taller than the other. The 7th and final floor were added in 1319, while the bell chamber was added
in 1372. By the time it was completed, the tilt was about 1 degree, or 2.5 ft (80 cm) from the
vertical. At its greatest, the tower leaned by an angle of 5.5 degrees (17.5 ft – 5.4 m – from the
vertical), though this has now been reduced to about 4 degrees.

The tower is about 60m high and was built to accommodate a total of seven main bells, cast to the
musical scale, ranging in weight from 650 kg to 3620 kg.