Alcala De Guadaira has a huge Moorish castle built by the Almohads and later altered by the Christians. During the Reconquest, many men were held prisoner in its dungeon, including Diego Garcia de Padilla of the Order of Calatrava. It is now in ruins but is still worth seeing. The town lies close to the River Guadaira which was once used to power a large number of water mills along its banks. The flour was used for supplying the city of Seville with bread.