Castles are large forts built on high cliffs or mountains during the Middle Ages.
Castles were homes to lords and ladies and were also homes for knights. Castles had thick walls and other defenses to protect the people who lived in the castle from the invaders. Castles could resist almost any land attack. Most castles were built in a similar way. Moats were deep ditches filled with dirty water dug around castles to stop invaders from entering.