Middle Ages. Main topic. How were castles built.

Defence 

The citizen would build castles on hills or peninsulas. There would be a drawbridge to keep the enemies out and also a portcullis (a gate of thick metal bars so that no one would get through). Between the drawbridge and portcullis was a narrow corridor. In the corridor arrow loops in the walls were used  as defence against enemies. There would also be a murder hole in the celling to drop stones or burning oil on enemies stuck between a drawbridge and portcullis. The castle would have a gatehouse and inside the house you could control the drawbridge and portcullis. Castles would have battlements known as merlons that would protect the guards walking on the walls from arrows.