Europe is a peninsula that runs westward from Asia and is comprised of over 40 countries and hundreds of languages. It covers around 3.9 million square miles and is mostly mountainous, with the Alps being a prominent mountain range. Its main rivers include the Rhine and Danube, and its climate is moderated by the Gulf Stream. Agriculture is a major industry, utilizing modern techniques. Most industry and population centers have developed near bodies of water. The population of Europe is over 740 million, densely populated compared to land area. Europeans have explored, colonized and spread their languages and influences around the world, though competition among countries has also led to wars and divisions.