This is cultural heritage of national interest and an impressive architectural testimony of the Andalusian city; it takes its name from the Saracen or suda well that plunges more than 45 metres deep before it reaches the level of the River Ebre. The site has the only outdoor Arabic cemetery in the whole of Catalonia and a state-owned hotel, Parador de Tursimo.
The castle was built in the 10th century, in the time of Abderraman III, on the site of the old Roman acropolis. The foundations and the walls, the well and the only outdoor Arabic necropolis in Catalonia still remain from the Islamic period. After the Reconquest it was converted into a prison and then during the reign of Jaume I into a royal residence. From the 15th Century, it was successively adapted to meet the new requirements for defence. It currently houses the state-owned hotel, Parador de Turismo.