Treni Cave or Wolf Cave is located in the western part of Small Prespa Lake, part of Devolli municipality. It has been declared a category I cultural heritage monument and a natural heritage monument due to the high historical, archaeological and natural values. Studies have revealed that this area has been inhabited since 6000 BC, making it one of the earliest settlements in the entire region. Treni Cave, in addition to its high cultural and historical values, is also famous for its biological values. Bats are the most important inhabitants of this cave. In fact 10 different species of bats have been observed in the cave, turning it into a very important point of biodiversity in the region.