Final answer:
A fortress that overlooks and protects a city is called a citadel. Citadels are commanding places that offer high levels of protection.
Step-by-step explanation:
A fortress that overlooks and protects a city is called a citadel. It is a commanding place that offers high levels of protection and is equipped for sieges. Citadels were typically located on defensible sites, such as hills or islands, and featured thick walls, controlled access points, and facilities for basic needs during times of war.