The Glockenturm – bell tower – like the Uhrturm, was spared demolition by the occupying French army in 1809. The four-storey octagonal bell tower of the former Renaissance Romanesque St. Thomas chapel (only foundations remaining today) was built in 1588 by order of Archduke Charles II and was designed by Antonio Marmoro and Giacomo della Porta.
In the deep cellar are former prison cells. On the fourth floor is the third largest bell of Styria – “Liesl” was cast 1587 in Graz by Martin Hilger. She has a diameter of 1.97 metres and weighs 4632 kg. One hundred and one strokes are rung on her every day at 7:00, noon and 19:00.