Towers, spires and fleches were an important feature of Gothic churches. They presented a dramatic spectacle of great height, helped make their churches the tallest and most visible buildings in their city, and symbolised the aspirations of their builders toward heaven. They also had a practical purpose; they often served as bell towers supporting belfries, whose bells told the time by announcing religious services, warned of fire or enemy attack, and celebrated special occasions like military victories and coronations. Sometimes the bell tower is built separate from a church; the best-known example of this is the Leaning Tower of Pisa.