The three great secrets of Mount Changbai, and the last one, you'll never guess.

Mount Changbai is known as the first sacred mountain in Northeast China due to its three mysterious features.

Firstly, the Tianchi of Mount Changbai is distinctive: it has no inlet but only an outlet, yet miraculously maintains its water level unchanged for hundreds of years. People speculate that perhaps rainwater and melted snow continuously replenish it, but these natural water sources seem insufficient to sustain the stability of Tianchi's water level. What's more puzzling is that despite being towering at the summit with an altitude of 2,189 meters, Tianchi continues to flow outward, seemingly relying solely on rainwater and melted snow, which is far from enough.

Secondly, despite the winter temperatures at Mount Changbai dropping to as low as minus 40 degrees Celsius, Tianchi's water never freezes, whether it flows gently or meanders to the Erdaobai River in the town, it always remains in a liquid state. People speculate that Tianchi's water temperature is relatively high, but the surrounding area is covered in ice and snow, making it difficult to explain this phenomenon. Even if there is a flow of hot spring water, it cannot explain why it does not freeze in the severe cold, as even hot spring water flowing for kilometers in minus 30-degree weather would turn into ice water.

The third mystery is Tianchi in summer, resembling a radiant emerald in the mountains but being a forbidden zone for life. In this water area, no fish can be found, not even the most basic plankton. It is commonly said that where there is water, there are fish, but in Tianchi of Mount Changbai, this saying seems to lose its meaning.

These mysterious phenomena have made Tianchi of Mount Changbai a puzzle in the minds of countless researchers and tourists. Perhaps it is the peculiar geological structure, perhaps the mysterious laws of nature, or perhaps the interference of other unknown factors. These mysteries await scientific unraveling. The mysteries of Mount Changbai fascinate and provoke deep thoughts on the mysteries of nature.