The Arab cistern, or aljibe árabe, is one of the oldest surviving structures in Setenil, predating the Christian conquest of 1484. It is built into the rock near the castle at the top of the village, a vaulted underground chamber that collected and stored water for the Moorish garrison and population above.
The cistern is small but well-preserved, and interpretive panels explain its construction and use. Access is sometimes possible on guided visits organised by the local tourist office; at other times the entrance gate is closed. It is worth asking at the Ayuntamiento if you want to see the interior. Even viewed from outside, the entrance arch and surrounding stonework are attractive examples of medieval Moorish civil engineering.