Iolani Palace, Honolulu (must see)
Iolani Palace has the distinction of being the United States' only royal palace to be used as an official residence by an actual monarch. It is located in downtown Honolulu, and is designated as a National Historic Landmark.
Before the Hawaiian monarchy was overthrown in 1893, Iolani Palace was a royal residence. It was used by both King Kalakaua and Queen Liliuokalani. When the Palace was no longer in use by the queen, it was used as a capitol building for the State of Hawaii until 1969. In 1978, the Palace underwent restoration, and was re-opened as a museum.
The area that Iolani Palace was built on was known as Pohukaina, a phrase which means “The land is calm.” It was part of the birthright of Kekauluohi, who served as Queen Consort to both Kamehameha I and II, and acted as Kuhina Nui (essentially a Prime Minister) of the Kingdom of Hawaii during the early to mid 19th century.
The building that sits on the grounds now is actually the second royal house to occupy the area. The first was a one-floor wooden building that consisted only of ceremonial rooms, not sleeping or living areas. The current building was commissioned by King Kamehameha V, to serve as a more modern royal palace inspired by the royal homes he had viewed on his visits to Europe.
Operation hours: Monday - Saturday 9 am – 4 pm.
Sight description based on wikipedia