The Place des Terreaux is located in the centre of Lyon, but in the early 13th century, the area was empty and suitable for constructing a defensive wall to protect the city from invaders. The wall extended between the Saône and Rhône (500 metres / 1640 feet long) and had a ditch that could be filled with water in case of siege. Gradually, the wall fell into disrepair and collapsed. In 1555, the nuns of the nearby convent of Saint-Pierre used the stones to repair the monastery (present-day Musée des Beaux-Arts de Lyon). The ditch was also filled with earth, allowing Simon Maupin (c.1625-1668) to build the Hôtel de Ville de Lyon on the square's eastern side between 1646 and 1651. The building suffered severe damage by fire in 1674 and was rebuilt by the French baroque architect Jules Hardouin-Mansart (1646-1708).