The Caucasus, a stretch of land between the Black and Caspian seas, and to the north and south of the Caucasian mountains, is such a hodgepodge of different religions and languages that, except for the two centuries of Russian rule and the imprint of seventy years of Soviet sameness, little else unifies its various peoples. Ethnically, the population of the Caucasus may be divided into four main groups: Iranian and Turkic peoples, Slavic newcomers, and so-called Caucasian peoples, such as Armenians and Georgians, who have no ties to any other nation. Some are Muslims, others are Christians. Among Muslims there are Sunni as well as Shia groups. The Christians include Georgian, Armenian, and Russian Orthodox denominations. There are also smaller national groups, neither Christian nor Muslim, such as the Buddhist Kalmyks of the northern steppe and the Jewish Tats of the mountain slopes. Numerous languages are spoken, some, like Georgian and Armenian, having no counterparts in the rest of the world and with alphabets of their own. Even the climate varies drastically, from subtropical on the Georgian Black Sea coast to the eternal snows of the high mountains; from bare high plateaus to fertile valleys.