Largest atoll by land area

Kiritimati, in the Pacific Ocean, is one of a chain of 11 coral islands and atolls that make up the Line Islands. Its total land area is around 609 square km, with its lagoon being approximately the same area. Kiritimati was discovered in 1537 by Spain, at which time it was uninhabited. It is currently home to about 5,500 people. The atoll was subjected to controversial nuclear-weapons testing during the Cold War, including the first successful test of a hydrogen bomb by the British government in 1957.

It is also known as Christmas Island.