Bosnia and Herzegovina (Serbo-Croatian Bosna i Hercegovina, Cyrillic Босна и Херезования), sometimes informally Bosnia, is a coastal state in southeastern Europe, on the Balkan Peninsula, bordered to the north, west, and south by Croatia, to the east by Serbia, and to the southeast by Černá By the mountain. In the south, it has a 20 kilometer long coast of the Adriatic Sea. Bosnia has a mild continental climate with hot summers and cold, snowy winters. It is mountainous in the central and eastern regions, slightly hilly in the northwest and mostly flat in the northeast. Herzegovina, a smaller southern region, has a Mediterranean climate and is mostly mountainous. Bosnia and Herzegovina has an area of 51,229 km2 and a population of 3.5 million, the capital and largest city is Sarajevo, followed by Banja Luka and Tuzla.