Gros Horloge

The Gros-Horloge is a 14th 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 having been 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.

Source: Wikipedia