Final answer:
Assyrian citadels like those at Nimrud, Dur-Sharrukin, and Nineveh were the centers of power containing royal palaces and temples, often protected by lamassu statues at their gates.
Step-by-step explanation:
Assyrian citadels were fortified areas that served as the power centers of Assyrian cities, containing royal palaces and temples. Examples of these citadels include the ones at Nimrud, Dur-Sharrukin, and Nineveh.
The citadel at Dur-Sharrukin, for instance, is famous for its impressive gates adorned with lamassu statues, which are mythological guardian figures with the head of a human, the body of a bull or lion, and massive wings. These figures symbolized power and protection and were believed to ward off evil. Within the citadels of these cities, the Assyrian kings built their luxurious palaces, thanks to the wealth amassed from successful military campaigns and the spoils of war.