Why is the Tower of Pisa tilted?

In 1172, Donna Berta di Bernardo donated 60 silver coins to the local cathedral for the purchase of stones to be used in the base of a new bell tower. The next year, construction on the tower began and almost immediately there were problems. read more

The Leaning Tower of Pisa is built on a site between the Arno and Serchio Rivers in Italy. The chief constituents of the soil on the site are hence clay, shells and fine sand. read more

When work on the tower resumed again, it was leaning 0.2 degrees north of vertical, but by the time the workers started on the seventh floor, the tower was tilting one degree south. Around this time, construction stopped again for unknown reasons. read more

The Leaning Tower of Pisa (Italian: Torre pendente di Pisa) or simply the Tower of Pisa (Torre di Pisa [ˈtorre di ˈpiːza]) is the campanile, or freestanding bell tower, of the cathedral of the Italian city of Pisa, known worldwide for its unintended tilt. read more