GROSSETO, Italy (AP) _ The Mafia plotted to blow up the leaning tower of Pisa as part of a strategy to attack Italy's cultural monuments, a prosecutor said Sunday.

A Mafia informer told investigators about the plan and pointed them to a cache of explosives to be used, Florence Prosecutor Piero Luigi Vigna said at a forum here.

The explosives were discovered last spring at Formello, 15 miles from Rome.

In 1993, a series of car bombs blamed on the Mafia struck the Uffizi museum in Florence and several churches in Rome. Authorities say the attacks were in response to Pope John Paul II's denunciation of the Mafia and a national crackdown on organized crime.