The Gros-Horloge is a 14th-century astronomical clock spanning the busiest pedestrian street in the old town, sitting between two pieces of Renaissance ornament — an arch below, a belfry tower above. The single golden hand on the blue-and-gold dial points to the hour; a small window above shows the day of the week with allegorical figures.
A spiral staircase inside the belfry leads to the clock mechanism (one of the oldest still ticking in Europe), then up to the roof for the best view in old Rouen — over the cathedral, the half-timbered houses, and the river. The climb is short but the rooms are tight.