Eastern Europe has varied physical geography, with cold and warm climates, jagged mountains, and rolling hills. Key landforms include the Northern European Plain, Carpathian Mountains, Great Hungarian Plain, Dinaric Alps, and Balkan Mountains. Major water features that aid in transportation and trade are the Adriatic Sea, Black Sea, and the heavily polluted Danube River. The region has a wide variety of climates and vegetation ranging from the coldest Baltic Coast with dense forests to the warmer and more Mediterranean Balkan Coast with beaches that attract tourists but fewer forests. Eastern Europe's forests were damaged by the nuclear disaster at Chernobyl in Ukraine, which released radiation into the air and soil.