Europe is one of the seven traditional continents of the Earth. Physically and geologically, Europe is the westernmost peninsula of Eurasia, west of Asia. Europe is bounded to the north by the Arctic Ocean, to the west by the Atlantic Ocean, to the south by the Mediterranean Sea, to the southeast by the Caucasus Mountains and the Black Sea and the waterways connecting the Black Sea to the Mediterranean. To the east, Europe is generally divided from Asia by the water divide of the Ural Mountains, the Ural River, and by the Caspian Sea.

Europe is the world's second-smallest continent in terms of area, covering about 10,180,000 square kilometres (3,930,000 sq mi) or 2% of the Earth's surface. The only continent smaller than Europe is Australia. Of Europe's 48 countries, Russia is the largest by both area and population, while the Vatican is the smallest. Europe is the third most populous continent after Asia and Africa with a population of 710,000,000 or about 11% of the world's population. However, the term continent can refer to a cultural and political distinction or a physiographic one, leading to various perspectives about Europe's precise borders, area and population.

Europe is the birthplace of Western culture. European nations played a predominant role in global affairs from the 16th century onwards, especially after the beginning of colonization. By the 17th and 18th centuries European nations controlled most of Africa, the Americas, and large portions of Asia. World War I and World War II led to a decline in European dominance in world affairs as the United States and Soviet Union took preeminence. The Cold War between those two superpowers divided Europe along the Iron Curtain. European integration led to the formation of the Council of Europe and the European Union in Western Europe, both of which have been expanding eastward since the fall of the Soviet Union in 1991.

Physiographically, Europe is the northwestern constituent of the larger landmass known as Eurasia, or Afro-Eurasia: Asia occupies the eastern bulk of this continuous landmass and all share a common continental shelf. Europe's eastern frontier is now commonly delineated by the Ural Mountains in Russia. The first century AD geographer Strabo, took the Tanais River to be the boundary, as did early Judaic sources. The southeast boundary with Asia is not universally defined. Most commonly the Ural or, alternatively, the Emba River serve as possible boundaries. The boundary continues to the Caspian Sea, the crest of the Caucasus Mountains or, alternatively, the Kura River in the Caucasus, and on to the Black Sea; the Bosporus, the Sea of Marmara, and the Dardanelles conclude the Asian boundary. The Mediterranean Sea to the south separates Europe from Africa. The western boundary is the Atlantic Ocean; Iceland, though nearer to Greenland (North America) than mainland Europe, is generally included in Europe. There is ongoing debate on where the geographical centre of Europe is. For detailed description of the boundary between Asia and Europe see transcontinental nation.

Because of sociopolitical and cultural differences, there are various descriptions of Europe's boundary; in some sources, some territories are not included in Europe, while other sources include them. For instance, geographers from Russia and other post-Soviet states generally include the Urals in Europe while including Caucasia in Asia. Similarly, numerous geographers consider Azerbaijan's and Armenia's southern border with Iran and Turkey's southern and eastern border with Syria, Iraq and Iran as the boundary between Asia and Europe because of political and cultural reasons. In the same way, despite being close to Asia and Africa, the Mediterranean islands of Cyprus and Malta are considered part of Europe.

Land relief in Europe shows great variation within relatively small areas. The southern regions, however, are more mountainous, while moving north the terrain descends from the high Alps, Pyrenees and Carpathians, through hilly uplands, into broad, low northern plains, which are vast in the east. This extended lowland is known as the Great European Plain, and at its heart lies the North German Plain. An arc of uplands also exists along the north-western seaboard, which begins in the western parts of Britain and Ireland, and then continues along the mountainous, fjord-cut, spine of Norway.

This description is simplified. Sub-regions such as the Iberian Peninsula and the Italian Peninsula contain their own complex features, as does mainland Central Europe itself, where the relief contains many plateaus, river valleys and basins that complicate the general trend. Sub-regions like Iceland, Britain and Ireland are special cases. The former is a land unto itself in the northern ocean which is counted as part of Europe, while the latter are upland areas that were once joined to the mainland until rising sea levels cut them off.

Europe lies mainly in the temperate climate zones, being subjected to prevailing westerlies.

The climate is milder in comparison to other areas of the same latitude around the globe. This is due to the Gulf Stream. The Gulf Stream is nicknamed "Europe's central heating", because it makes Europe's climate warmer and wetter than it would otherwise be. The Gulf Stream does not only carry warm water to Europe's coast but also warms up the prevailing westerly winds that blow across the continent from the Atlantic Ocean.

Therefore the average temperature throughout the year of Naples is 16 °C (60.8 °F), while it is only 12 °C (53.6 °F) in New York City which is almost on the same latitude. Berlin, Germany; Calgary, Canada; and Irkutsk, in the Asian part of Russia, lie at about the same latitude. But January temperatures in Berlin average about 15 °F (8 °C) higher than those in Calgary, and they are almost 40 °F (22 °C) higher than the average temperatures in Irkutsk.

The Geology of Europe is hugely varied and complex, and gives rise to the wide variety of landscapes found across the continent, from the Scottish Highlands to the rolling plains of Hungary.

Europe's most significant feature is the dichotomy between highland and mountainous Southern Europe and a vast, partially underwater, northern plain ranging from England in the west to Ural Mountains in the east. These two halves are separated by the mountain chains of the Pyrenees and Alps/Carpathians. The northern plains are delimited in the west by the Scandinavian Mountains and the mountainous parts of the British Isles. Major shallow water bodies submerging parts of the northern plains are the Celtic Sea the North Sea, the Baltic Sea complex and Barents Sea.

The northern plain contains the old geological continent of Baltica, and so may be regarded geologically as the "main continent", while peripheral highlands and mountainous regions in the south and west constitute fragments from various other geological continents. Most of the older geology of Western Europe existed as part of the ancient microcontinent Avalonia.

Since the Renaissance and the Age of Discovery, Europe has had a major influence in culture, economics and social movements in the world. European demographics are important not only historically, but also in understanding current international relations and population issues.

Some current and past issues in European demographics have included religious emigration, race relations, economic immigration, a declining birth rate and an aging population. In some countries, such as the Republic of Ireland and Poland, access to abortion is currently limited; in the past, such restrictions and also restrictions on artificial birth control were commonplace throughout Europe. Furthermore, three European countries (The Netherlands, Belgium and Switzerland) have allowed a limited form of voluntary euthanasia for some terminally ill people.

In 2005 the population of Europe was estimated to be 728 million according to the United Nations, which is slightly more than one-ninth of the world's population. A century ago Europe had nearly a quarter of the world's population. The population of Europe has grown in the past century, but in other areas of the world (in particular Africa and Asia) the population has grown far more quickly. According to UN population projection (medium variant), Europe's share will fall to 7% in 2050, numbering 653 million. Within this context, significant disparities exist between religions in relation to fertility rates. The average number of children per female of child bearing age is 1.52. According to some sources, this rate is higher among Muslims. In 2005 the EU had an overall net gain from immigration of 1.8 million people, despite having one of the highest population densities in the world. This accounted for almost 85% of Europe's total population growth.