The Gros-Horloge is a fourteenth-century astronomical clock in Rouen, Normandy.
The clock is installed in a Renaissance arch crossing the Rue du Gros-Horloge. The mechanism is one of the oldest in France, the movement was made in 1389. Construction of the clock was started by Jourdain del Leche who lacked the necessary expertise to finish the task, so the work was completed by Jean de Felain, who became the first to hold the position of governor of the clock.The clock was originally constructed without a dial, with one revolution of the hour-hand representing twenty-four hours. The movement is cast in wrought iron, and at approximately twice the size of the Wells Cathedral clock, it is perhaps the largest such mechanism still extant. A facade was added in 1529 when the clock was moved to its current position. The mechanism was electrified in the 1920s and it was restored in 1997.
Coordinates 49°26'29.532" N 1°5'28.457" E