Of the dozens of defensive towers medieval Bologna's rival families once built, only a handful survive, and none rival the pairing at Porta Ravegnana: the Asinelli, at 97 meters the taller of the two, and its shorter, more dramatically tilted neighbor, the Garisenda.
Both went up between 1109 and 1119, and Dante mentions the Garisenda's lean directly in the Inferno, comparing a giant he meets to the tower as seen from beneath its overhang. For decades, climbing the Asinelli's 498 steps for a view over Bologna's red rooftops was the city's classic small ordeal. The Garisenda’s lean is a genuine structural concern, and both towers still dominate Piazza di Porta Ravegnana.





