The Lokvarka cave is the largest cave in Gorski Kotar. It measures 1200 metres in length and 140 metres in height from the highest to the lowest point of its explored area, making it one of the largest caves in Croatia adapted for tourist visits. The entrance to the cave was discovered by accident, in 1911, during the quarrying of stone in a small quarry. That same year, the cave was visited and researched by Dr Josip Poljak, and the following year, paths and wooden bridges and fences were set up throughout the cave to make it suitable for tourist visits. Paths leading through the cave were first renovated in 1935, and then again in 1961 and 1974 to replace the wooden bridges with iron bridges, and electric lighting was also added. The cave underwent its fourth round of renovations in 2012.

Adapted and lit paths and stairs can be used to access a few different galleries, all the way down to the underground lake. The cave is naturally divided into four galleries with numerous stone decorations. Three of them are open for visitors, while the fourth – the latest to be discovered – was preserved in its original state. The cave temperature measures at around 8 °C year-round, and the flora and fauna remain partly unexplored. The cave boasts stunning deposits, especially flowstones, as well as an endemic fauna, among which the most famous are the subterranean spider Parastalita stygia, the millipede Brachydesmus inferus inferus, subterranean beetles Thyphlotrechus bilimeki and Parapropus sericeus stilleri, the subterranean leech and others.