Schools of California Online Resources for Education
Score: Castle Builder
A lesson plan with plenty of discussion and research questions, as well as links to examples and more information. You'll also find extension ideas and adaptations for students with special needs.
Tech4Learning
Pics4 Learning: Images for Education: Castles
A treasury of photos of various castles from around the world! Although the images do not contain much information, they can be used as a visual reference for students of all grade levels.
Birmingham Museums Trust (UK)
Birmingham Museum & Art Gallery: A Stone Keep
A diagram showing how a lord would be protected if his house was attacked.
Curated OER
Educational Technology Clearinghouse: Clip Art Etc: Drawbridge
The drawbridge of a castle.