Malpas Tunnel

The Malpas tunnel carries the Canal du Midi under the d'Ensérune hill in Hérault, France.

Excavated in 1679, it was Europe's first navigable canal tunnel and is a monument to the determination of Pierre-Paul Riquet, the chief engineer.

The advice of the Chevalier de Clerville, architect to Louis XIV, was to cross the river Aude rather than tunnel through the hill.

Riquet's response was to ask his master mason, Pascal de Nissan, to continue tunneling in secret despite the risk of collapse.

The tunnel is 165m long with an arch 8m above the canal's surface,[1] and removed the necessity for an extra lock.