卫城，特指雅典的卫城，或泛指任何城市的卫城。

人类进入农耕时代后，需要进入平原进行耕作。然而平原相对于山区的不利因素是其易攻难守，于是早期的人们在山下平原修建城市的同时也在城市附近的山区修建被称为卫城的军事要塞。这样做的目的是，一旦城市受到战争的威胁，居民们可以迁移到易守难攻的卫城进行持久战、消耗战。如此可以降低财产和人口的损失。

维基共享资源中相关的多媒体资源：卫城

An acropolis (Greek: ἀκρόπολις; from akros or akron, "highest", "topmost", "outermost" and polis, "city"; plural in English: acropoles, acropoleis or acropolises) is a settlement, especially a citadel, built upon an area of elevated ground—frequently a hill with precipitous sides, chosen for purposes of defense. In many parts of the world, acropoleis became the nuclei of large cities of classical antiquity, such as ancient Rome, and for this reason they are sometimes prominent landmarks in modern cities with ancient pasts, such as modern Rome.