Traduction :
secure as a city protected by a wall of metal and a moat of boiling water (idiom); well fortified; invulnerable to attack
Référence :
金属造的城，滚水形成的护城河。形容工事无比坚固。
Origine :
《汉书·蒯通传》：“必将婴城固守，皆为金城汤池，不可攻也。”
Exemple :
大沽口的炮台，如能得他允许保护，～。（高阳《胭脂井》）
Annotation :
固若金汤1
1. gùruòjīntāng :
[EN] secure as a city protected by a wall of metal and a moat of boiling water (idiom); well fortified; invulnerable to attack
