Europe has several physical characteristics. It includes four peninsulas and three main islands. It is home to many fjords and two major mountain ranges, the Alps and Pyrenees. Rivers such as the Danube, Rhine, Seine and Thames are important. It has a varied climate affected by ocean currents. Economically, many industrial centers developed near coal and iron deposits. Trade and transportation links, like rivers, canals and the Chunnel are significant. Culturally, Europe was the birthplace of democracy, the industrial revolution and has had a large influence globally through colonization and alliances like NATO.