Pisa Lean

The Leaning Tower of Pisa in Italy is perhaps the most famous bell tower in the world. Work started on it in 1173 and it was not completed still 1372. After the first three storeys were finished the ground below it began to sink. That caused the tower to lean. Every year it leaned a little more. Efforts have now been made to keep it from falling over.

The tower is about 17 feet (5 m) out of line. But engineers hope that they have stopped in form leaning any future and falling over.

In 1994 they placed 660 tons (600 t) of lead on the tower's base. The straightened the tower by 0.4 inch (1 cm). Then in 1995 they buried 10 steel cables 164 feet (50 m) in the ground and attached them to the tower. These reduced the lean by another 1 inch (2.5 cm).