Many wealthy castles had canons. Some castles were built by rivers which helped to stop invaders too. Construction and defenses of a castle are very fascinating. Building a castle can take a very long time. Enemies would attack a castle for months so the people in the castle would run out of food.
Castles are very damp and cold.
Living in a castle could be hard, but they were strong and could last a long time. Castles have many strong defenses. Castles and Moats. Kingfisher books, 1994. The World of Castles and Forts.