The course of Spanish history changed 2km west of Santa Elena on 16 July 1212, when Christian armies defeated the Muslim Almohad army in the battle of Las Navas de Tolosa, which opened the doors of Andalucía to the Reconquista. This museum, a few hundred metres west from A4 exit 257, tells the fascinating story and has a viewing tower from which you can see the (now-overgrown) battle site.
After the battle the Christians are believed to have tossed Muslim captives off the cliffs of the Desfiladero de Despeñaperros. It's commonly believed this is the origin of the name Despeñaperros, which means 'overthrow of the dogs'.