The Japanese occupation of the Gilbert Islands was the period in the history of Kiribati between 1941 and 1945 when Imperial Japanese forces occupied the Gilbert Islands during World War II, in the Pacific War theatre.
From 1941 to 1943, Imperial Japanese Navy forces occupied the islands, and from 1942 until 1945 Ocean Island which was home to the headquarters of the Gilbert and Ellice Islands colony (GEIC).
Operation Grapple was a set of four series of British nuclear weapons tests of early atomic bombs and hydrogen bombs carried out in 1957 and 1958 at Malden Island and Kiritimati (Christmas Island) in the Gilbert and Ellice Islands in the Pacific Ocean (modern Kiribati) as part of the British hydrogen bomb programme. Nine nuclear explosions were initiated, culminating in the United Kingdom becoming the third recognised possessor of thermonuclear weapons, and the restoration of the nuclear Special Relationship with the United States in the form of the 1958 US–UK Mutual Defence Agreement.
During the Second World War, Britain had a nuclear weapons project, codenamed Tube Alloys, which was merged with the American Manhattan Project in August 1943. Many of Britain's top scientists participated in the Manhattan Project. After the war, fearing that Britain would lose its great power status, the British government resumed the atomic bomb development effort, now codenamed High Explosive Research.