The prevalent definition of Europe as a geographical term has been in use since the mid-19th century. Europe is taken to be bounded by large bodies of water to the north, west and south; Europe's limits to the east and north-east are usually taken to be the Ural Mountains, the Ural River and the Caspian Sea; to the south-east, the Caucasus Mountains, the Black Sea and the waterways connecting the Black Sea to the Mediterranean Sea. 27 European states are members of the politico-economic ...