It is the largest of the Earth's oceanic divisions. Its name is derived from the Latin name Mare Pacificum, "peaceful sea", bestowed upon it by the Portuguese explorer Ferdinand Magellan. It extends from the Arctic in the north to Antarctica in the south, bounded by Asia and Australia in the west and the Americas in the east. At 169.2 million square kilometers (65.3 million square miles) in area, this largest division of the World Ocean – and, in turn, the hydrosphere – covers about 46% of the Earth's water surface and about 32% of its total surface area, making it larger than all of the Earth's land area combined. It is neither easy nor especially useful to generalize about the vast, sparsely populated region of the Pacific Ocean, which covers one-quarter of the Earth's surface. The myriad small islands peppered across the ocean all have unique features of geography, economy and political history. Some are genuinely independent, some internally self-governing with foreign and security policies controlled elsewhere, while a handful remain colonies. The military influx during the 1970s and 1980s has left a legacy of airfields, storage depots, port complexes, intelligence-gathering, early-warning and other ‘support' facilities. But islanders are well aware that they must develop their own economic systems to survive, and have focused on principal areas. One of these is tourism. Much of the region is within reach of the North American traveler, although difficult for others both financially and in terms of transport. On a darker note, a number of islands face a serious threat to their land masses due to global warming and rising sea levels. Some, such as Nauru, could disappear altogether - it has already lost one, albeit uninhabited, island. The Pacific islands are consequently an increasingly vo