Laohei Shan — Old Black Mountain — is the main volcanic cone at Wudalianchi and the most rewarding climb in the area. The ascent from the base takes about 40 minutes on a well-marked trail through the black lava field, and the crater rim provides the defining view of the whole site: a perfect bowl crater below you, and beyond it the five linked lakes stretching across the flat terrain, the lava fields spreading in every direction. On a clear day the scale of the 1719–1720 eruption becomes fully legible from up here.
The crater interior is accessible by steps cut into the rock. The walls show alternating bands of different lava flows, and the geological layering visible in the crater cuts is impressive even without specialist knowledge. The walk is easy by any standard and should not be missed — the view from the rim is the essential Wudalianchi experience. Bring water; there is no shade on the lava field and summer temperatures can be high.