1. In 1803, King Kamehameha I of Hawaii united the islands of Maui, Molokai, Lanai, and Kahoolawe into one Hawaiian kingdom.

2. On December 15, 1840, King Kamehameha III signed the 'Act to Organize the Executive Departments of the Government,' which established Hawaii's first Cabinet departments.

3. In 1893, Queen Liliuokalani, the last reigning monarch of the Hawaiian Kingdom, was illegally overthrown by a group of American businessmen and politicians on December 15. This event is known as the overthrow of the Hawaiian Kingdom.

4. December 15, 1939, marked the opening of the Honolulu International Airport, which has since become the main airport serving the state of Hawaii.

5. On December 15, 1941, just days after the attack on Pearl Harbor, martial law was declared in Hawaii, giving the military complete control over the islands. It would last until October 1944, well after the end of World War II.