Just below the entrance to the castle is a huge rock, which was once home to Enna's Temple of Demeter (Ceres to the Romans), goddess of fertility and agriculture. The temple, built in 480 BC by the tyrant Gelon, is supposed to have featured a statue of King Triptolemus, the only mortal to witness the rape of Demeter's daughter Persephone.
There's not much left of the temple now, but the rocky platform, accessible by a series of steep steps, is a great place for a picnic or to take in the sunset.