<P> One - quarter of the Soviet Union consisted of mountains or mountainous terrain . With the significant exceptions of the Ural Mountains and the mountains of eastern Siberia, the mountains occupy the southern periphery of the Soviet Union . The Urals, because they have traditionally been considered the natural boundary between Europe and Asia and because they are valuable sources of minerals, were the most famous of the country's nine major ranges . In terms of elevation (comparable to the Appalachians) and vegetation, however, they are far from impressive, and they do not serve as a formidable natural barrier . </P> <P> Truly alpine terrain was found in the southern mountain ranges . Between the Black and Caspian seas, for example, the Caucasus Mountains rose to impressive heights, marking a continuation of the boundary separating Europe from Asia . One of the peaks, Mount Elbrus, is the highest point in Europe at 5,642 meters . This range, extending to the northwest as the Crimean and Carpathian mountains and to the southeast as the Tien Shan and Pamirs, formed an imposing natural barrier between the Soviet Union and its neighbors to the south . The highest point in the Soviet Union, at 7,495 meters, was Mount Communism (Pik Kommunizma) in the Pamirs near the border with Afghanistan, Pakistan, and China . The Pamirs and the Tien Shan were offshoots of the tallest mountain chain in the world, the Himalayas . Eastern Siberia and the Soviet Far East are also mountainous regions, especially the volcanic peaks of the long Kamchatka Peninsula, which jutted down into the Sea of Okhotsk . The Soviet Far East, the southern portion of Soviet Central Asia, and the Caucasus were the Soviet Union's centers of seismic activity . In 1887, for example, a severe earthquake destroyed the city of Verny (present - day Almaty), and in December 1988 a massive quake demolished the Armenian city of Spitak and large sections of Kirovakan and Leninakan . The 1988 quake, one of the worst in Soviet history, claimed more than 25,000 lives . </P> <P> The Soviet Union possessed both scarce and abundant water resources . With about 3 million rivers and approximately 4 million inland bodies of water, the Soviet Union held the largest fresh, surface - water resources of any country . But most of these resources (84 percent), as with so much of the Soviet resource - base, lay at a great distance from the majority of potential users; they flowed through sparsely populated territory and into the Arctic and Pacific oceans . In contrast, areas with the highest concentrations of population (and therefore the highest demand for water supplies) tended to have the warmest climates and highest rates of evaporation . This resulted in barely adequate (or in some cases inadequate) water - resources in the areas of most need . </P> <P> Nonetheless, as in many other countries, the earliest settlements sprang up on the rivers, where the majority of the urban population preferred to live . The Volga, Europe's longest river, became by far the Soviet Union's most important commercial waterway . Three of the country's twenty - three cities with more than one million inhabitants stood on its banks: Gorky, Kazan, and Kuybyshev . </P>

Who claimed most of the land in the center of the continent