Crown

Imperial State Crown of the United Kingdom
Corona di Costanza d'Aragona.
Imperial Crown of Kingdom of Sicily (Crown of Constance of Aragon, Cathedral of Palermo).
Imperial Crown (Benkan) of Emperor Kōmei of Japan
Imperial Crown of Austria
Imperial Crown of Russia, 2012 replica
Vajracarya's Ritual Crown, Ancient Nepal
The Seobongchong Golden Crown of Ancient Silla, which is 339th National Treasure of South Korea. It is basically following the standard type of Silla's Crown. It was excavated by Swedish Crown Prince Gustaf VI Adolf in 1926.

A crown is a traditional form of head adornment, or hat, worn by monarchs as a symbol of their power and dignity. A crown is often, by extension, a symbol of the monarch's government or items endorsed by it. The word itself is used, particularly in Commonwealth countries, as an abstract name for the monarchy itself (and, by extension, the state of which said monarch is head) as distinct from the individual who inhabits it (that is, The Crown). A specific type of crown (or coronet for lower ranks of peerage) is employed in heraldry under strict rules. Indeed, some monarchies never had a physical crown, just a heraldic representation, as in the constitutional kingdom of Belgium.