description: The Optimistic cave - the first cave on continent and the second in the worldby length of the labyrinth. For present-day mark on the map 212 kilometersunderground passages! The biggest and one of most beautiful of gypsum caves.Speleology. A history ofdiscovery of the Optimistic cave. Expeditions. Research. Thedescription. A photo. Speleotourism. Aktive and extrem tourism |