That is a story has been told for a long time by the people live on the ground. Here is a large and tall castle in the ground under one big lake. One day, groups of people digged tunnel under the ground and discovered this subterranean void. They find that the building is connected by lots of bridges with beautiful glasses and delicate gothic style pillars. Like the whole building is the crossroads of the underground world. They walked on one of these bridges that located in the middle of the building. When they were walking, the whole building is really quiet but just the sounds of raindrops that hit the glass. When they followed the sound and looked outside the window, here was raindrops everywhere with faint blue light seems like the raindrops absorb the mineral in the ground. It looked like the entire building is crying. When they walked into the building, they did not find even one person but a considerable number of books lying on the ground. When they clean a path from the book hill. They did not find the stairs to go down or up the floors. Finally, they find one handle on the ‘elevator’ but controlled by the chains. They move the handle and took the elevator to discover the castle and enjoy the rain scene from the huge french window. And then they went to the huge library with spiral walkway, the gallery, the courtyard, the private library with gorgeous iron arches, the room in the caves, and the planetarium. It took them like thousands of years to get back to the ground, when they bring reporters and hundreds of people to went back to the library, they find there just stones and muds at the end of the tunnel.