The Leaning Bell Tower of Pisa has been included in the list of the World Heritage Sites by United Nations Educational, Scientific and Cultural Organization since 1987. Over the last twenty years, the Tower has successfully undergone a number of interventions to reduce its inclination. Despite its importance in the Italian cultural heritage, no studies about the dynamic behaviour of this monument had been carried out until the 1990s. Starting from the results obtained by the Committee for the Safeguard of the Tower, a novel investigation campaign about the dynamic parameters characterising the Tower has begun in 2014. This paper aims at discussing the main results obtained until today. After a short history of the construction and of the interventions on the Tower, the following topics... are discussed: a review of historical seismicity, dynamic identification, definition of seismic input, site response analysis, and seismic response accounting for soil-structure interaction. The studies made on the Tower highlight the importance of soil-structure interaction in the survival of the Tower due to strong seismic events since the middle ages.