In the begging of 12 century the tower architecture was not the same as it is today. It was the longest one though in those days but the tilt the tower has was happened because unstable foundation choose for the tower. While it was under construction the tower was tilt due to soft foundation from one side. Later the tilt was improved by making some measurements to make it stable.From 1991-2001 the tower was under surface restoration to make it stable. By doing it in May 2008 the tower was announced as in perfect stable condition.
