Postoina cave is located in Slovenia and is the second largest cave in Europe. There are many scenic spots in the cave, and the cave is a spectacle. The cave is connected by tunnels, forming a wonderful cave promenade. There are 4 main caves such as the brilliant hall, the slow hall, the crystal hall, the concert hall, etc., especially the concert hall scenery, which is like a palace. The sound effect in the cave is very good. The cave is also rich in high-hanging bell milk and upright stone, some like giant gem flowers, ice crystal jade; some like Santa Claus, smile can be; or like a lion down the mountain, or like a bird spread its wings, colorful and dry. The underground river flowing through the cave was ignored, sometimes clear and quiet, sometimes rapids.