The Arab Baths of Jaén are among the largest and best-preserved hammams of medieval al-Andalus, dating from the 11th century when Jaén was an important taifa kingdom. Four rooms — cold, warm, hot, and a steam chamber — survive almost intact, with horseshoe arches, star-shaped skylights, and channels for the water in the floor.
The whole complex sits beneath the Palacio de Villardompardo and is accessed through the same ticket. Combined with two excellent small museums in the upper floors (popular arts and naive art), this is the single best visit in the city after the cathedral. Free entry for EU citizens, otherwise €3.50.