Final answer:
Kings and queens wear symbolic crowns or headdresses such as the medieval open crown, the winged crown, and the phoenix crown at official ceremonies, reflecting their authority and national identity.
Step-by-step explanation:
A king or queen wears regal headdresses or crowns at official ceremonies. These are not just ornaments but powerful symbols of authority and national identity. Crowns have been an integral part of royal attire across various cultures and time periods, varying in style and decoration.
For instance, the traditional medieval open crown was often adorned with symbols such as the fleur-de-lys, indicating the monarch's right to rule. In ancient Egypt, the nemes headdress or the protective cobra (uraeus) signified kingly power, while in Iran, royal figures might wear a winged crown, a symbol of authority dating back to the Sasanian kings.
In China, an empress's phoenix crown (fengguan) could be highly decorated with rare feathers, beaded birds, gold dragons, and gems such as rubies, sapphires, and pearls, with the number and type of embellishments reflecting her rank. Furthermore, the head of state's role goes beyond merely wearing ceremonial attire; they serve as national symbols unifying the country by participating in national celebrations and hosting significant events.