The continent of Europe is not a clearly defined geographical unit. It is physically attached to Asia and forms the western end of the immense Eurasian land mass. For historical reasons it has been treated as a separate continent.

What constitutes Europe is a debatable issue. There is a core area that includes countries such as France and Germany, but the boundaries are not clear cut. A number of physical features are traditionally used to define Europe. These do not neatly match the political and economic reality of Europe, especially in the east of the continent. Seas and oceans form the boundaries to the north (Barents Sea), the west (Atlantic Ocean) and the south (Mediterranean Sea). Although these water boundaries appear distinct, in reality this is not always the case. The countries around the Mediterranean Sea have a very long history of trade and political links. Consequently some countries of southern Europe have far more in common with countries in Africa or the Middle East than they do with the Scandinavian countries in the north of Europe (see Scandinavia, history of).

The traditional physical boundary of the eastern edge of Europe is a line following the Ural Mountains and the Ural River to the Caspian Sea, westward through the Caucasus Mountains to the Black Sea, and through the channel often called the Turkish straits that includes the Bosporus, the Sea of Marmara and the Dardanelles. This boundary splits Russia between Europe and Asia. It also means that most of Turkey is outside Europe, apart from a small portion north of the Bosporus. This last contains Istanbul (Constantinople), which historically was an important European city; it was the heart of the Byzantine Empire and the Ottoman Empire, both of which ruled a large part of southeastern Europe. Turkey, like Russia, has historic ties to both Europe and Asia.

On the edges of the main land mass of Europe are a number of important island groups. Great Britain, Ireland, and Iceland are separate nations. The Mediterranean Sea contains some major islands that are part of other nations. Sardinia and Sicily, for example, belong to Italy. Generally, while some smaller island groups, such as Malta, are independent nations, most small islands are subsumed in other countries; for example, the Orkney Islands, Shetland Islands, and Channel Islands are associated with Britain and are thus all part of the United Kingdom. Norway, with its numerous fjords and very irregular coastline has 150,000 small coastal islands.

Although it includes the western part of the vast country of Russia, Europe is still a relatively small continent; only Australia is smaller. Europe contains just 7% of the world’s land area and about 10% of its population. More than half of Europe’s 43 countries have a population of less than 10 million. Only six European countries have populations of more than 50 million.

Europe’s significance in the world stems not from its size but its influence, its history, and its relative prosperity. Over the last 2,000 years many of the world’s most influential political ideas, economic systems, technological innovations, and cultural movements have originated in Europe. The Greek and Roman civilizations , the Renaissance, the age of exploration, and the Industrial Revolution are all examples of historical periods in which European influence was extended to other parts of the world. This influence has often been beneficial, but it has also led to the exploitation and oppression of non-European peoples through colonialism. In the 1930s nine European countries (the United Kingdom, France, Italy, Belgium, Portugal, Spain, the Netherlands, and Denmark) still had significant overseas possessions. Most former colonies became independent nations in the years after World War II, but their development continued to be shaped by their past European links. During its existence the world’s leading Communist country, the Union of Soviet Socialist Republics (USSR, 1917-91), influenced the development of communist satellite states in Europe, Asia, Africa, and Latin America.

The history of Europe has witnessed periods of both upheaval and stability. The late 20th century is no exception. The upheaval of World War II (1939-45) weakened the economies of Europe and led to the division of the continent during the cold war between the nations of Eastern Europe in the Soviet bloc and those in the west that were neutral, nonaligned, or aligned with the United States. Many of the countries of Western Europe received U.S. economic aid through the Marshall Plan, and a number of them entered the North Atlantic Treaty Organization (NATO; established in 1949).

For the West European countries the 1950s and ’60s were a period of relative economic stability and growth, despite the political tension of the cold war and the loss of former colonies. A number of organizations were established to promote economic and political stability. The European Economic Community (Common Market) was formed in Western Europe in 1958 to promote the benefits of economic cooperation, the removal of customs barriers, and the free movement of labor. The European Community, or European Union (EU), established in 1967, has provided the same West European nations with common political institutions that have legislative and judicial functions. Examples are the European Parliament in Strasbourg, the European Court of Justice in The Hague, and the European Commission in Brussels. While the nations that are members of the European Union have to abide by certain regulations and laws, they remain sovereign powers with their own political and legislative institutions.

In world terms the countries of Western Europe have high levels of economic development and together form a very important world market and influential economic bloc. Consequently, major corporations from the two other powerful economic blocs, Japan and the United States, have concentrated much of their overseas investment in Europe.

During the cold war period, political and economic institutions in Eastern Europe were determined by the Soviet Union’s control of that region. The Eastern European countries belonged to a political alliance, the Warsaw Treaty Organization, and an economic grouping, the Council for Mutual Economic Assistance (Comecon).

The late 1980s and early 1990s were a period of relative upheaval. Economic recession affected a number of European nations leading to high unemployment. More significantly, between 1989 and 1991 many existing political structures in Eastern Europe collapsed and the Iron Curtain that had divided Europe since 1945 disappeared. The Soviet system of satellite nations broke down and institutions such as Comecon were abolished. Communist regimes disappeared from most Eastern European countries. National boundaries were redrawn, and 12 new European nations were established. Czechoslovakia split into two nations, the Czech Republic and Slovakia. Belarus, Estonia, Latvia, Lithuania, Moldova, and Ukraine, all former Soviet republics, are now independent nations.