This fascinating village about 1.5km beyond Moon Hill is a treasure trove of traditional Qing dynasty architecture. Beyond the initial, slightly cheesy scenic area at the beginning, you reach the village proper, where you can get lost in a maze of tight lanes. Look out for the old Opium Den (烟馆, Yānguǎn) at No 89 Longtan Cun, which didn't close till 1940, and note the village's carved upturned lintels, astonishingly regular brickwork and ample distribution of Cultural Revolution slogans.
Other buildings of note include the small 驰á尘é苍 (衙门) and the Xu Family Shrine (徐氏宗祠), but the terrific karst background is all part of the overture. The name Longtan means 'Dragon Pool', after the deep pool by the hamlet. Take the turning after Moon Hill for the village.