The Bay of Kotor ( Montenegrin and Serbian: Boka kotorska/Бока которска, pronounced [bɔ̂ka kɔ̂tɔrskaː]), known simply as Boka, is a winding bay of the Adriatic Sea in southwestern Montenegro. The bay, once called Europe's southernmost fjord, is in fact a ria of the disintegrated Bokelj River which used to run from the high mountain plateaus of Orjen.