Castillo de Oreja is a medieval fortress in ruins overlooking the Tajo valley and Mar de Ontígola near Toledo, standing on the site of the ancient Roman city of Aurelia. Built as a Muslim castle and later conquered by Alfonso VII in 1139, it features a strong rectangular tower surrounded by walls following the irregular cliff edge. The fortress played a crucial role in medieval Christian-Muslim conflicts and is partially isolated on a plateau bordering the Tajo. Access requires walking rural trails with steep inclines, though multiple routes are available from surrounding towns.