The 221-stepped tower, built in 1456, has long ceased to serve its original purpose as a fire watchtower. In the former lodgings of the tower-keeper, who signalled imminent danger by sounding the bell, there is a permanent exhibition about the history of the New Town, its Town Hall and the adjoining Charles square. It also presents some of the oldest Prague panoramas, capturing how Prague looked from high vantage points around the whole Prague basin. The exhibition consists of copies of historical engravings from the Prague City Museum archives.