Mont-Saint-Michel Dam (Barrage du Mont-Saint-Michel)

The bronze railings on the dam feature the "Pupitre des Lettres" (Lectern of Letters) - four alphabets engraved to honor the medieval monks who worked in the Mont's scriptorium. Hebrew and Arabic read right to left (east to west, matching the site's orientation), while Greek and Latin read left to right. The Latin text uses Carolingian minuscule script, developed during Charlemagne's reign.

Before the dam's construction, the bay was losing its maritime character due to silting caused by the 1879 causeway and 1966-1969 barrage. Scientists projected that by 2040, Mont-Saint-Michel would be permanently surrounded by salt marshes rather than water. The bay receives approximately 3 million cubic meters of sediment annually.

Each of the eight gates weighs 50 tonnes (20-tonne mechanism plus the gate itself) and measures 8 meters wide by 9 meters high. The gates can operate bidirectionally - a first in France - allowing water flow in both directions depending on tidal conditions. During operation, the dam can release water at 100 cubic meters per second, ten times the natural average flow of the Couesnon River.