In Europe which area is called Bulkans and Why?

The most serious source of nationalist tension in Europe after 1871 was the area called the Balkans. The Balkans was a region of geographical and ethnic variation comprising modern-day Romania, Bulgaria, Albania, Greece, Macedonia, Croatia, Bosnia-Herzegovina, Slovenia, Serbia and Montenegro whose inhabitants were broadly known as the Slavs. A large part of the Balkans was under the control of the Ottoman Empire.