Dragon VAT Tiankeng is a long axis of 350 meters and a short axis of 170 meters The oval Tiankeng with a depth of 350 meters ranks third in China and fifth in the world. The inner wall of the cylinder is like cutting, with pine and cypress lying on the wall seam, and ancient vines hanging upside down. The bottom of the cylinder spits green all the year round, and hundreds of birds contend. Because it is a natural large stone cylinder, it is also known as the "first cylinder in the world" because of the wonderful legend of the love between woodcutter and dragon girl.