Leaning Tower of Pisa

The widow

A widow's bequest paid for the first stones of the tower

On 5 January 1172 Donna Berta di Bernardo left sixty soldi toward the bell tower. The sum bought a few stones that still form its base. The foundations were laid on 9 August 1173.

The sinking

It began to sink at the second floor, and war saved it

In 1178 the tower began to sink when the work reached the second floor, because its foundation was only three metres deep in weak ground. Building stopped for the better part of a century while Pisa fought Genoa, Lucca and Florence, which let the soil settle.

The curve

Builders made the upper floors taller on one side, so it curves

Work resumed in 1272, and to offset the tilt the engineers built the upper floors with one side taller than the other. That is why the tower is curved. The seven bells are tuned to the notes of the major scale.

199years, across three stages of building

Galileo

Galileo is said to have dropped cannonballs from the tower

Between 1589 and 1592 Galileo Galilei, who lived in Pisa, is said to have dropped two cannonballs of different masses from the tower to show that they fall at the same speed. The main source is a biography by his pupil Vincenzo Viviani, written in 1654 and published in 1717.

The fix

The tower was closed in 1990 and soil was taken from under it

After the tower closed on 7 January 1990, engineers removed 38 cubic metres of soil from under the raised end, and lead counterweights were added from 1993. The tilt fell by 45 centimetres, and the tower reopened on 15 December 2001.