The Cook Islands has created one of the world's largest marine sanctuaries, protecting a vast swathe of the Pacific Ocean more than three times the size of France. Environmentalist Kevin Iro, who first proposed the idea more than five years ago, said it was a landmark achievement that would help preserve the ocean for future generations. The Cook Islands has a population of just 10,000 and its 15 islands have a combined landmass of 236 sq km, barely the size of Washington DC.