Vajont Dam, Decommissioned arch dam in Erto e Casso, Italy

Vajont Dam is a disused double-arch dam of 360,000 m³ of concrete in Erto e Casso, province of Pordenone, 100 km north of Venice. Its pale grey face, 261.60 m high, curves inward between the rock walls of the Vajont gorge, with a straight crest topped by a parapet and a metal catwalk crossing the face midway down.

The facility was completed in the early 1960s to generate hydroelectric power for the region. In October 1963, a massive rockslide from Monte Toc triggered a wave that overtopped the wall and destroyed several villages downstream.

The dam's name comes from the Vajont stream, pronounced "Vaiònt" locally. The structure stands in the municipality of Erto e Casso, and the disaster of 9 October 1963 is tied to its name in local memory. The reservoir behind the wall is kept almost completely empty for safety reasons.

Visits take place from spring to autumn with guided walks that explain the engineering and events. Access involves narrow paths along the rock faces, so sturdy shoes and a reasonable level of confidence on uneven ground are recommended.

The concrete wall itself remained almost undamaged despite the enormous forces released during the catastrophe. Geologists continue to study the surrounding slopes to understand how hillside movements interact with human structures.