Towards the lower end of the Tang Valley, the tumbling waters of the Tang Chhu slow and widen at the photogenic Mebar Tsho, or "Burning Lake." A traditional wooden bridge crosses the gorge, and tsha-tsha - simple offerings shaped out of clay - fill rocky niches, hinting at the lake's important place in the Buddhist legends that suffuse this area and its intimate connection to Bhutan's great treasure-finder, Pema Lingpa.
When Guru Rinpoche visited Bhutan, he was believed to have strewn the country with relics and religious texts. These treasures were to remain hidden until a virtuous treasure-finder, or terton, came looking for them. Mebar Tsho yielded two such treasures to Pema Lingpa. On the first occasion, Pema Lingpa beheld a temple on the bottom of the lake and dived in to visit it, returning with a chest of relics.
It was Pema Lingpa's second visit to the lake, however, that left Mebar Tsho with its striking name. Accused of trickery, Pema Lingpa jumped into the lake holding a burning lamp, saying that if he was a genuine terton he would return with the lamp still lit. His audience had just begun to wonder if he had drowned when he emerged on a rock at the side of the lake, dripping wet and clasping a statue, with his lamp still burning brightly.
Today, spectators can observe the lake from the bridge or from a rock ledge beyond it; especially nimble visitors can climb down the rocks to the very banks of the lake. Mysteriously, bubbles appear prolifically on the surface of the water, which the Bhutanese believe may originate from a complex series of tunnels underneath Mebar Tsho.