Monk sea cave is 160 m deep and about 14 m wide cave narrows towards the end where it is a bit shabby. It is located in the southern part of Biševo, in the bay Trešjavac. Its name derives from the fact that this cave was the habitat of a Mediterranean bear, the smallest species of seals which are among the most endangered mammals in the world, and are referred to as "sea cows" in Vis. Today, it is unfortunately rarely seen in the Adriatic today. Source vis-central.com