Mammoth Cave is one of the largest known cave systems in the world. Two projects were chosen, which is very good.
Such attractions have also been seen in China! general
I recommend everyone to go to a park for a lot of fun
Mammoth Cave is the first U.S. national park visited, and this park features underground cave tours. The landscape in the cave is ever-changing, and the open area can be used as a conference hall. The narrow place is like a line of sky. It is always up and down, flat and tortuous. When entering the cave, the flowers-like crystals make people linger. When exiting the cave, it is called Niagara Falls. The stalactites are breathtaking, and a sense of satisfaction arises spontaneously, and I want to come again.