9. Northwestern Europe
Western Europe, like India, is a peninsula of Asia. A maximum definition would include all the territory that came to form part of western Christendom in the Middle Ages.  This domain stretches from Spain and Italy in the south to Scandinavia in the north, from Ireland in the west to Lithuania in the east.
Northwestern Europe encompasses Britain, the Low Countries, and northern Germany. These are as among the most densely populated parts of the world. The region lies at the same latitude as Labrador and the Kamchatka, two forlorn and frigid peninsulas that typify a vast swath of territory located too close to the Arctic for human comfort. Yet Europe, and especially northwestern Europe, stands out in sharp contrast to North America and Asia. Unlike Labrador and the Kamchatka, this region enjoys a temperate climate: a winter that is not so cold as to preclude the survival of a dense population, a summer that allows an adequate growing season, and plenty of rain. This climate is the gift of the Atlantic or, more precisely, of the way seawater circulates in it, bringing warm tropical water to the shores of Europe. Like so much else in the world, this system is likely to be contingent. There may have been no such pattern of circulation in the last ice age, and there may be none when the climate takes its next lurch. Perhaps nowhere is the idea of a fleeting Holocene window of opportunity more in place than in northwestern Europe.