This contribution focuses on detecting the causes of the collapse of the Asciello Bridge, located in Cautano, in the Benevento area, Italy. The bridge was built in the 1860s. Towards the end of World War II, it was demolished during the retreat of the German Nazist army and subsequently rebuilt in the early post-war years. In the 1960s, the bridge collapsed, likely due to a landslide, and was never reconstructed. This study investigates the bridge collapse using the discrete element method. The numerical analysis was conducted on a 2D geometry reconstructed from a point cloud obtained via laser scanning. The bridge geometry was carefully discretised using rigid elements with unilateral contact, featuring Mohr-Coulomb friction at the interfaces. The arch geometry was reconstructed following an in-depth geometrical and damage analysis. Specifically, the portion of the bridge still standing was directly derived from laser scanner data, whereas the collapsed section was hypothesised by referring to engineering principles outlined in post-war technical treatises and, importantly, in analogy with its “twin bridge” built near it. A parametric kinematic investigation was performed for several imposed increasing settlements simulating a landslide affecting an abutment of the bridge. The parametric study confirmed that the collapse was caused by differential settlement, characterised by a horizontal displacement component of approximately 90 cm, with an inclination on the horizontal plane between 15 and 25 \(^\circ \) .