Landlocked and largely mountainous in the west and south, Serbia lies within several mountain systems: the Dinaric Alps in the west, the Kopaonik range in the southwest, and the Balkan Mts. in the east. Much of Serbia slopes generally north toward the Danube and Sava rivers and is drained chiefly by the Drina (which forms part of the western border), Kolubara, Morava, and Timok rivers and their tributaries. The northeast is part of the fertile Danubian plain; it is drained by the Danube, Sava, Tisa (Tisza), and Morava rivers. Politically, the country consists of Serbia proper with the cities of Belgrade, Niš, and Kragujevac and the ethnically mixed Vojvodina province with Subotica and Novi Sad. The Sanjak, or Sandžak, region, which straddles the Serbia-Montenegro border, is home to many Muslims.
The population consists primarily of Serbs, with Magyar (Hungarian), Romani (Gypsy), Bosniak, Montenegrin, and other minorities. The Serbs are very closely related to the Montenegrins and closely related to the Croats. but have been marked by different historical experiences. The Serbs also distinguish themselves culturally from the Croats through their membership in the Orthodox Eastern rather than Roman Catholic church and through the differences between Serbian and Croatian (forms of Serbo-Croatian), most obviously the use of the Cyrillic rather than the Roman alphabet.