At the first sign of trouble, the commoners rushed to get inside the castle walls before the gates closed and shut them out.
Location: Castles were usually built on top of a hill, if one was handy. That way, the lookout guards could more easily spot attackers approaching.
The Moat: A moat was built around many of the castles. This was a deep ditch surrounding the castle walls, filled with water. A bridge was built to cross the moat. The bridge was raised during an attack. The moat was loaded with traps and sharp spikes in case someone tried to swim across.
The Keep: One of the largest spaces behind the thick walls was the keep. The keep was a storage area topped by a huge square tower with slotted windows for castle archers to use. The keep stored food, wine, and grain in case of siege.
The Barracks: Other buildings made up the barracks. the barracks were the homes of the knights and their families.
The Great Hall: The Great Hall was a passageway that connected the lord's home to the keep.
The Chapel: The chapel was build either inside the lord's home or as a separate building. The chapel was a place to hold religious services.
The Gatehouse: The gatehouse was a building used by the guards at the gates. The portcullis was the grating of iron bars at the gateway. (medievaleurope)
Here play with the Castle
And one interesting web about Medieval Arms Race
TAREA : EXPLICA LA DIFICULTAD QUE PODÍA SUPONER APODERARSE DE UN CASTILLO Y QUÉ ARMAS MEDIEVALES PODRÍAN SER LAS MÁS EFICACES. PUBLÍCALO EN TU BLOG