Italy's northeast and the nearby Balkan areas are a diverse part of the world, due no doubt to difficult topography. Beyond the valleys of the Po, Sava, and Drava, a multitude of mountains crowd each place. In the upper left the Lago di Garda shows its form against a fine sample of terminal moraines. Its sister valley just to the east seems the result of flood events when the main valley was choked with ice. On the Po Plain the streams from the north have dug valleys into the margins of the foothills, yet from the south side the streams have built naturally-leveed courses above the surrounding land. The Balkan half on the right side offers many fine islands and gorges, and is prime cycling terrain.