Bosnia and Herzegovina (Босна и Херцеговина), abbreviated BiH or B&H, sometimes called Bosnia–Herzegovina and often known informally as Bosnia, is a country in Southeastern Europe, located in the Balkans. Bosnia and Herzegovina borders Serbia to the east, Montenegro to the southeast, and Croatia to the north and southwest. In the south it has a narrow coast on the Adriatic Sea within the Mediterranean, which is about long and surrounds the town of Neum. Bosnia, which is the inland region of the country, has a moderate continental climate with hot summers and cold, snowy winters. In the central and eastern regions of the country, the geography is mountainous, in the northwest it is moderately hilly, and in the northeast it is predominantly flat. Herzegovina, which is the smaller, southern region of the country, has a Mediterranean climate and is mostly mountainous. Sarajevo is the capital and the largest city of the country followed by Banja Luka, Tuzla, Zenica and Mostar.
The area that is now Bosnia and Herzegovina has been inhabited by humans since at least the Upper Paleolithic, but evidence suggests that during the Neolithic age, permanent human settlements were established, including those that belonged to the Butmir, Kakanj, and Vučedol cultures. After the arrival of the first Indo-Europeans, the area was populated by several Illyrian and Celtic civilizations. Culturally, politically, and socially, the country has a rich and complex history. The ancestors of the South Slavic peoples that populate the area today arrived during the 6th through the 9th century. In the 12th century, the Banate of Bosnia was established; by the 14th century, this had evolved into the Kingdom of Bosnia. In the mid-15th century, it was annexed into the Ottoman Empire, under whose rule it remained until the late 19th century. The Ottomans brought Islam to the region, and altered much of the country's cultural and social outlook.
From the late 19th century until World War I, the country was annexed into the Austro-Hungarian monarchy.