People built castles for protection and defense. Many castles are associated with legends about royalty and supernatural beings. Some castles, like Windsor Castle, are famous for their paintings and treasures and are said to be haunted by past kings and queens. Other notable castles mentioned include Balmoral Castle, where Prince Albert and Queen Victoria lived, and the Tower of London, known for its guards in distinctive uniforms. Legend also connects certain castles to figures like King Arthur and Merlin, with some believing their ghosts still inhabit the castles' tunnels.