The Leaning Tower (13th century), one of the landmarks of Toruń, was a typical fortified tower, built as a part of the defensive  city wall system at the turn of the 14th century. Originally, the tower was open on the town-facing side and included a gallery for guards who day and night made rounds, patrolling the city walls. In the 18th century the fourth wall was added and the tower became a prison for women; in the 19th century the tower was turned into a forge and a gunsmith’s quarters. The tilt of the 15-metre (49.2 feet) tower is currently 146.171 cm,  i.e. 5°13'15 off the perpendicular on the side of the street. This anomaly, caused by ground subsiding under its foundations, has been willingly explained by legends.