Keep towers are fortified structures commonly found in medieval castles. They served as a residence for the lord and his family, as well as a place of refuge during attacks. Built with thick stone walls, keep towers were designed to withstand sieges and provide a secure living environment. These towers often featured multiple floors, with the upper levels used for living quarters and the lower levels for storage or defense. The design typically included narrow windows for archers and a central staircase for access. Examples of keep towers can be seen in many historic castles across Europe, such as Tower of London and Dover Castle.