 Additionally, the ancient coastline was situated much farther inland than today's; it gradually shifted outward over centuries and the new land was developed throughout the 20th century.Rione Cittadella, in the western area of the centre, was the most important district of the city and included the Municipal palaces, Castel Sismondo and the Cathedral of Santa Colomba.Rione Clodio, towards the north, was popular and a peculiar urban structure tied with the near Marecchia river.