A karst phenomenon, a 110-meter-long cave rich in stalactites and stalagmites that you can see on the hiking route from Omišalj and Njivica while enjoying untouched nature.

Biserujka Cave is a karst phenomenon 110 meters long, rich in stalactites and stalagmites. It was also called Vitezić's cave or Slivanjska pit. The cave, which today is one of the least known but paradoxically the most visited speleological sites in Croatia, has been a destination for early tourists who left graffiti there since the 19th century. It is located on the edge of the Omišalj Municipality above the Slivanjska bay and next to the village of Rudine. It has been known since ancient times, and according to legend, it got its name from the pirate treasure that was found there.