On December 7, 1941, the Japanese attacked Pearl Harbor, Hawaii, with the intention of destroying the Pacific Fleet of the United States Navy. The attack succeeded in damaging or destroying almost 20 U.S. ships and over 300 planes. It also resulted in the death of 2,403 military personnel and civilians. Approximately 1,000 people were wounded as well. On the next day, December 8, the United States declared war on Japan. Soon afterwards, it declared war on Germany and Italy, and the United States had officially entered the global conflict of World War II.

At the time of the United States entry into the war, Hawaii was not a state but an American territory. The economy of Hawaii, which depended mainly on pineapple and sugar exports, had suffered as a result of the Great Depression. Many people were unemployed.

After the Pearl Harbor attack, martial law was declared throughout Hawaii. Some authorities thought that it would be best to imprison people of Japanese descent, but because they comprised about 37 percent of the population, it was not a practical approach. Instead, severe martial law regulations applied to everyone, but Japanese people were watched particularly carefully. Authorities froze wages and suspended union activity, civilian courts, and civil liberties. Barbed wire went up on beaches and in other areas. A complete blackout and curfew was imposed from sunset to dawn. Photography along the coastline was forbidden. The authorities rationed food and severely restricted bars and the sale of liquor.

On the other hand, the vast influx of military personnel gave a boost to the Hawaiian economy. Construction increased and businesses were established to cope with the demand for more shops, restaurants, and residences.

After the war, the economy slumped again as military personnel went home. However, Hawaiian businesses were eventually able to recover as tourism to the islands became more popular. Tourists now come from all over the world to visit Pearl Harbor, which is one of Hawaii's most popular attractions. Its sites include the USS Arizona Memorial, the Battleship Missouri Memorial, the USS Bowfin Submarine Museum, and the Pacific Aviation Museum.