national treasure
noun [ C ] uk/ˌnæʃ.ən.əl ˈtreʒ.ər/ us/ˌnæʃ.ən.əl ˈtreʒ.ɚ/
（被某个国家引以为自豪的人或物）国家财富
someone or something of which a particular country is very proud
The veteran actress has become something of a national treasure. 这位从业多年的女演员已经成了某种国家财富。