More About These Jigsaw Puzzels The castle, acropolis, alcazar, château, citadel, donjon, estate house, fasthold, fastness, fort, fortification, fortress, hold, keep, manor, mansion, palace, peel, safehold, stronghold or tower has always fascinated us from a very young age. A castle (from Latin: castellum) is a type of fortified structure built in Europe and the Middle East during the Middle Ages by nobility. A European innovation, castles originated in the 9th and 10th centuries, after the fall of the Carolingian Empire resulted in its territory being divided among individual lords and princes. Many castles were originally built from earth and timber, but had their defences replaced later by stone. Early castles often exploited natural defences, and lacked features such as towers and arrowslits and relied on a central keep. Daily Jigsaw Puzzles features the most beautiful, well known and imposing castles in the world in our online jigsaw puzzles.