The famous bell tower in Pisa (in northwestern Italy) leans because of the unstable soil on which it was built. Construction began in 1173 on the approximately 180-foot campanile; it began to lean as soon as the first three floors were completed. Nevertheless, building continued, and the seven-story structure was finished between 1360 and 1370. Leaning a bit more each year, by the time it was closed for repairs in 1990, the tower tilted 14.5 feet out of line when measured from the top story. Engineers on the project worked to stabilize the foundation and straighten it slightly (to prevent damage). The tower, which was built alongside a church and a baptistery, would probably not be remarkable if it were not for its slant. But with its characteristic angle, it continues to attract tourists to the small town on the Arno River.