zhè zuò / gǔ dài / yào sài / jiàn / zài / shān dǐng / ， / yì shǒu nán gōng / ， / shì / lì shǐ shàng / zhòng yào / de / jūn shì / fáng yù gōng shì / 。

这座古代要塞建在山顶，易守难攻，是历史上重要的军事防御工事。

This ancient stronghold is built on the top of a mountain, easy to defend and hard to attack, and is an important military defense work in history.