FR-63. Grand Arc is a natural bridge type meander located near the village of Saint Martin-de-Londres on the canyon "Ravin des Arc" on Lamalou river in Hérault department of France. The long distance footpath GR 60 (red and white marked trail) passes close to the bridge. The natural bridge has a measured height of 15 meters and a span of 9 meters. The stream bed is usualy dry on the summer except stagnante potholes. There is permanently water under the bridge in the giant pothole. The natural bridge is located at "Grand Arc" on the IGN topographic map number 2742 east "Ganges" pleat F1.