If the word atoll conjures up images of the Maldives, the vast majority of the world's 400 atolls are located in the Pacific. The Tuamotu, which cover a territory as vast as western Europe 1800km (1125mi) long, 600km (375mi) wide, are undoubtedly the main group with 78 islands, 77 of them being atolls, the exception being Makatea, a raised coral island whose phosphate pits have been mined to exhaustion. This dusting of islands is also called The Labyrinth, or the Archipelago of the Rough Sea and has remained essentially uncharted due to the difficulty of navigating the local waters. The exotic appearance of these atolls are linked to the palm trees which have only been growing since 1860. Until then, the eroded peaks of the 2000-3000m (6100-9100ft) underwater mountains were merely flat barren patches of dead coral and white sands with no fresh water or soil to grow anything. In addition, the earlier natives, the Paumotus, were aggressive towards visitors, indulging in tribal wars and cannibalism until it was annexed to French Polynesia in 1880. In 1842, Darwin wrote that these atolls were the tops of old volcanoes and his theory was confirmed decades later. Mururoa and Fangataufa was the site for the now infamous nuclear testing program run by the French Government in the SE corner of the Tuamotu's.