[Something's] value is worth several cities
Refers to something extremely costly and/or precious
Positive
美术馆中许多价值连城的艺术品被盗 | Měishùguǎn zhōng xǔduō jiàzhíliánchéng de yìshùpǐn bèi dào
Many priceless works of art were stolen from the arts museum
[Source]
一块那么大、而又无瑕疵的绿宝石会是价值连城的 | Yīkuài nàme dà, ér yòu wú xiácī de lǜbǎoshí huì shì jiàzhíliánchéng de
A flawless emerald of this size is worth a fortune
[Source]
A king's ransom
To be worth a fortune
连城之价 (lián chéng zhī jià)
连城之碧 (lián chéng zhī bì)
None
《史记》(Shǐ Jì), or the famous work "Records of the Grand Historian" by 司马迁 (Sī Mǎ Qiān).
See the story for 完璧归赵 (wán bì guī zhào | to return something intact to its owner)