An impregnable fortress; a strong and secure city; an unassailable stronghold.
这座古老的城堡依山傍水，地势险要，真是金城石室，易守难攻。
This ancient castle, situated by mountains and water, occupies a strategic and dangerous terrain, making it truly an impregnable fortress, easy to defend and difficult to assault.
Era:
Ancient
Frequency:
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