Calatayud boasts the oldest fortified complex on the Iberian Peninsula built by the Arabs, dating back to the 8th century. These were defensive castles, with five castles connected by walls and specific entry gates into the city. The Terrer and Zaragoza gates are still preserved. The castles include Castillo Mayor, Torre Mocha, Castillo de la Peña, Castillo del Reloj, and Castillo de Consolación.