Europe is a continent that comprises the westernmost peninsula of Eurasia. It is generally divided from Asia by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting the Black and Aegean Seas. Europe, in particular ancient Greece, is the birthplace of Western culture. It played a predominant role in global affairs from the 15th century onwards. Europe lies mainly in the temperate climate zones, being subjected to prevailing westerlies. The European climate is milder in comparison to other areas of the same latitude around the globe due to the influence of the Gulf Stream, which not only carries warm water to Europe's coast, but also warms up the prevailing westerly winds that blow across the continent from the Atlantic Ocean.