Piusa caves are one of the most visited tourist sights in South Estonia. Unique colonnades that are kilometers long were created during the mining of glass sand in the 1920’s. In the Nature Reserve (45.64 ha) of the cave’s area is a marked hiking trail of 1.4 km. Piusa Caves are the largest wintering area of bats in the Baltic States. Seven species of bats (pond bat, Daubenton’s bat, Brandt's Bat, Whiskered Bat, Natterer's Bat, common long-eared bat, Northern bat) have been found here, and the number of specimens extends to 3000. Piusa caves can be visited only with a guided tour through the visitor center.