A gatehouse is a fortified structure, often located at the entrance of a castle or walled complex. It serves as a protective barrier, featuring a combination of defensive elements such as thick walls, towers, and battlements. The gatehouse typically contains a large door or gateway, which can be closed and secured to control access to the enclosed area. It acts as both a defensive feature and a symbol of authority, guarding the entrance to the castle or complex and providing a first line of defense against potential intruders.