Following severe weather in Tuscany, a sudden collapse of a 35-meter-wide section of Volterra’s city walls occurred on January 31, 2014. Subsequently, a GBInSAR LiSAmobile radar system was installed to create a pre-alert monitoring system. This system accurately and specifically detects real-time displacements of the city’s southwestern side, including walls, buildings, and monuments, facilitating prompt interventions for citizen safety. The efficacy of the LiSAmobile system became evident when it clearly identified precursors to a subsequent major wall collapse. Since monitoring began, the GBInSAR LiSAmobile system measured a constant displacement rate of 0.1 mm/hour on a 15-meter-high wall supporting the Acropolis and hosting an underground parking lot. Following a sudden increase in displacement values up to 1.7 mm/hour, local authorities were alerted two days before the collapse, allowing time to secure the area and implement safety measures.