No snakes or frogs

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Myths aside, the lake is not connected with any outside waterway. The only water it gets is from rainfall and underground water seeping from the surroundings.

The crystal-clear lake never overflows or dries up. It is self-regulated within a reasonable range. Local tour guides say there are no snakes or frogs in the lake or the vicinity, and nobody can account for their absence. Also among those vanishing are the dead leaves from trees that, unlike elsewhere, are not seen floating on the lake.

However, volcanic sediments, said to be 50 meters deep at the bottom of the lake, may contain the key to the changes of the ecology over the millennia.

As the lake is situated at the intersection of the monsoon from East Asia and the one from the southwest, it is extremely receptive to changes in weather patterns. No wonder it has been used as a spot for field study by both UNESCO and the Chinese Academy of Sciences.

But you do not have to be a science buff to enjoy the park. Take the rocks. A boardwalk will take you along a volcanic rock wall where rock strata in hundreds of layers reveals volcanic activities in the distant past. You can also disregard the science and appreciate them as nature's sculptures. Some of the walls display a variety of natural patterns that resemble abstract paintings. Others provide shelters for wild birds in their alcoves.

Where bare land is not visible (only the vertical walls are exposed), giant roots and twisted rattan of ancient trees stretch over boulders the size of cottages. As roots expand, plants that grow in rock fractures may splinter the rocks in a process called "root wedging".

Plants may grow on top of other plants as a result of germination through bird feces, rain or wind. The aerial roots of these plants often wrap around their host plants' stems, strangling them in an effort to reach downwards into the ground where they eventually gain nutrients directly.