The Leaning Tower of Pisa

The Leaning Tower of Pisa has been leaning almost since building started in 1173

In 1990 it was closed to the public because it was leaning too much! But following engineering work to return it to an angle of 85° it has been reopened this summer.

The tower is a hollow cylinder 16m (52 feet) in diameter and 55m (180 feet) tall.

Click on the picture for the maths!