Bologna`s towers were important for warning and defensive purposes and were naturally a sign of prestige for the families who lived in them. At the end of the 12th century there were one hundred of them, today around fifteen remain. The two towers are the symbol of Bologna. The taller one is Asinelli Tower built in the 10th century. It is 97 m high. The base was modified in 1488 to house guards. The smaller is Garisenda Tower, a contemporary of its neighbor. Its strong inclination is striking, caused by an earlier greater settling of the land.