Location: N57° 50` 34.3", E27° 28` 28.7"
Piusa caves are situated in Orava parish, Põlva county. The caves are man-made and were created as a result of manual mining of unique white sand. The quartz sand was used to make glass. The caves were dug from 1922 to 1966. Altogether there are 10 km of underground tunnels. The caves consist of two networks of caves with crossing galleries having sandstone columns and vaulted ceilings. Six older caves in the western part are up to 3 metres high and tens of metres long. Two eastern caves are up to 10 metres high and more than 100 metres long. The largest caves have also got names: Good cave, Fox cave, Bride Hill cave, Museum cave, Big cave. Unfortunately, all caves have not been marked on maps and their exploration is complicated because the tunnels are dangerous and may collapse. Some tunnels are already impassable. People are not allowed to enter anymore. Since 2001, the visitors can only see the entrance of the caves and only with a tour guide. The caves near entrance are 2 to 3 metres long tunnels separated by 5 to 6 metres thick pillars.
How was sand mined in Piusa?
The work in the mine was done by shovels, pick-axes and raw manpower. These methods were used until 1927 when the new mining tunnel was opened. Now the workers didn't load sand out of the boxes to the bags anymore, but sand boxes were carried out of the mine by horses to the wagons. In 1930 the third mine was opened and the branch of railway was built and connected to the main one. In 1933 the 4th mine was established and the railway track led into the tunnels. In 1965 the safer way of mining started which meant mining in the open-pit mine.
Piusa caves have become a popular site for hibernating bats. It is the largest known hibernation colony in Eastern Europe. Seven species of bats have been found there and the number of specimens extends to 3,000. Since 1981 the caves are protected as a Nature Reserve. The suitability of caves depends on specific conditions like temperature and humidity, silence, darkness, the size of a cave, the size of entrance holes, existence of cracks and surroundings of the cave. The condition of Piusa caves has been suitable for bats for a long time and this has made the increase of the colony possible.
There is also a legend about the caves that they had been connected by a secret tunnel with the Pskovo-Pechersky Monastery which was used by the monks. Today the spirits of the monks still haunt people in the caves.