The Five Colored Pool at the top of the Huanglong valley is the climax of the boardwalk walk, a cluster of shallow pools whose colours range through turquoise, jade, gold, and vivid white depending on the depth and angle of light. At 3,700 metres, this is the highest point accessible to most visitors in the park, and the altitude — together with the fact that you have just spent two hours walking uphill — gives the arrival some earned quality that cable car arrivals do not quite replicate.
The pools are best in the morning light, when low sun catches the calcium formations at an angle that maximises the colour contrast. By midday the light is overhead and flatter, and the queues at the viewing platforms are at their worst. The pool complex covers a significant area and there is enough variety — some pools are a few centimetres deep and almost white, others are a metre deep and the dense turquoise of tropical sea — to reward extended looking. Budget at least thirty minutes here before beginning the descent.
The small Buddhist temple just below the Five Colored Pool is dedicated to Huanglong, the Yellow Dragon spirit associated with the mountain. It is active and modestly visited; the prayer wheels and incense burners frame the pools below in a way that makes for good photographs and provides the site's religious dimension, which the park's tourist infrastructure otherwise tends to elide.