Tianmen Mountain rises immediately behind the city of Zhangjiajie and offers a spectacle quite different from the sandstone columns of Wulingyuan. Its defining feature is the Heaven Gate Cave: a natural arch about 130 metres high and 57 metres wide formed in 263 AD when the back of a cliff cave collapsed, leaving an opening that frames the sky like a window punched through solid rock. The name Tianmen — Heaven's Gate — refers to this arch, and it is visible from the city below, the cable car, and the plateau above, each angle producing a completely different impression.
The cable car from the city centre is reputedly the world's longest alpine passenger cableway at around 7.5 kilometres, climbing nearly 1,300 metres over 28 minutes. The view from the gondola down onto the forested ridgelines and the town receding below is arresting even before the destination becomes visible. At the top, the mountain road winds along the rim of the plateau in 99 hairpin turns — a route used for the Tianmen Mountain Road Race and now marketed as a scenic bus experience. Three separate sections of glass-floored walkway are bolted to the cliff edges above drops of several hundred metres; each costs ¥5 to walk, and the middle section, the Coiling Dragon Cliff, is the most exposed.
The Heaven Gate Cave itself requires climbing 999 steps, or using escalators on a parallel route, to pass through. Standing in the arch and looking out through the opening toward the cloud layer below is the mountain's best single experience. The plateau above the arch is forested and dotted with small temples, including Tianmenshan Temple at around 1,500 metres, which appears on clear days to float between layers of mist.
A combined ticket covering entrance, cable car, and internal buses costs around ¥275. The mountain is reached directly from Zhangjiajie city by cable car or by bus via the mountain road; the round trip takes a full day. Wulingyuan is a separate destination requiring at least another day, so visitors to this part of Hunan should plan for a minimum of two days in the Zhangjiajie area.