A bird's eye view of Rehai from the mountain top. [Photo by He Na/China Daily]

In fact so fantastical is this place, with its great concentration of high-temperature springs and out-of-this-world scenery, that visitors can barely put down their cameras, so eager are they not to miss the picture-postcard scenes that await them around each and every corner.

As is seems to be almost obligatory in many such places in China, there a legend, and a beautiful one at that, attached to it. In ancient times, it seems, Tengchong was a freezing place, and the misery of those who lived there was appropriate to the circumstances. A kind old man keen on improving the lot of his people made tortuous efforts to do something about it, but to no avail. These efforts moved a god, who handed him a pearl and told him to put it in his mouth. The man, suddenly overcome by heat and thirst, drank from the waters of several rivers and turned into a small dragon spraying hot water.

The places he visited were left with countless hot springs. From that point, the legend goes, Tengchong's fortunes changed: the weather became balmy, harvests became abundant and Rehai was left with the steamy riches it enjoys to this day.

You will find that charming tale retold in a museum at the foot of the mountain, and I strongly recommend you spend an hour or so there reading detailed explanations－these ones a bit more scientific－of each of Rehai's hot springs. Once you have filled your brain with that knowledge, the sense and visual experience you are about to have will be a lot more meaningful and enjoyable.

Not far from the entrance is a big hot spring waterfall that is the result of a tectonic rupture that left the Zaotong River at two levels.

Night and day, the cascading waters put on a majestic display, producing a gigantic shroud of billowing steam as they crash down, sending sound waves throughout the valley and beyond.