Answer:
The Balkans region is surrounded by mountains and connects Europe with Asia. The land bridge is a route between the Mediterranean and Black Seas and is divided between the Roman and Byzantine Empires. By the 1400s, the peninsula was ruled by Muslims. The assassination of Archduke Ferdinand led to World War I and Yugoslavia was eventually formed. Similarly, the Baltic States have a location along the Baltic Sea, which provided trade and transportation benefits but also made them susceptible to invasion. These three countries spent much time under Russian and Soviet control. After regaining independence, the nations formed alliances such as the NATO for protection. Meanwhile, Ukraine, which lies between Asia and Europe, suffered economically under Soviet control with famine and radioactive fallout from the Chernobyl disaster. Finally, Russia's geographic features protect its lands and enabled its expansion. It ruled most of northern Eurasia and became a world power along with the U.S. during the Cold War. Problems within the Soviet Union and rebellion by its republics brought the end of the Soviet Union.