The Leaning tower of Pisa. The Leaning Tower is actually the free-standing bell tower, or campanile, of Pisa Cathedral. The cathedral itself was begun in 1064. The tower was under construction from 1173MB-1372, is 55MB metres high, and has foundations only 3 metres deep in the soil. Soon after construction began it started to lean. Some of the upper storeys were placed off centre to try to counteract the lean. At present, the top of the tower is about 4 metres off vertical, a tilt of about 4.2 degrees, and the tower is in danger of collapse. Scientists are trying to devise a way to reduce the tilt to about 3 degrees and to stabilise the foundations.