crown jewels

Từ điển Oxford Advanced Learner 8th

ˌcrown ˈjewels [crown jewels] BrE NAmE noun plural
the crown and other objects worn or carried by a king or queen on formal occasions

Culture:
The British Crown Jewels are kept for the public to see in the ↑Tower of London and include several crowns, sceptres (= a decorated rod carried as a symbol of power) and swords. Only two small items are from before 1660, as the original Crown Jewels were destroyed during the Commonwealth under Oliver Cromwell.